Config,Darwin: Allow for configuring Darwin to use embedded runpath.

Recent Darwin versions place contraints on the use of run paths
specified in environment variables.  This breaks some assumptions
in the GCC build.

This change allows the user to configure a Darwin build to use
'@rpath/libraryname.dylib' in library names and then to add an
embedded runpath to executables (and libraries with dependents).

The embedded runpath is added by default unless the user adds
'-nodefaultrpaths' to the link line.

For an installed compiler, it means that any executable built with
that compiler will reference the runtimes installed with the
compiler (equivalent to hard-coding the library path into the name
of the library).

During build-time configurations  any "-B" entries will be added to
the runpath thus the newly-built libraries will be found by exes.

Since the install name is set in libtool, that decision needs to be
available here (but might also cause dependent ones in Makefiles,
so we need to export a conditional).

This facility is not available for Darwin 8 or earlier, however the
existing environment variable runpath does work there.

We default this on for systems where the external DYLD_LIBRARY_PATH
does not work and off for Darwin 8 or earlier.  For systems that can
use either method, if the value is unset, we use the default (which
is currently DYLD_LIBRARY_PATH).

ChangeLog:

	* configure: Regenerate.
	* configure.ac: Do not add default runpaths to GCC exes
	when we are building -static-libstdc++/-static-libgcc (the
	default).
	* libtool.m4: Add 'enable-darwin-at-runpath'.  Act  on the
	enable flag to alter Darwin libraries to use @rpath names.

gcc/ChangeLog:

	* aclocal.m4: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.
	* config/darwin.h: Handle Darwin rpaths.
	* config/darwin.opt: Handle Darwin rpaths.
	* Makefile.in:  Handle Darwin rpaths.

gcc/ada/ChangeLog:

	* gcc-interface/Makefile.in: Handle Darwin rpaths.

gcc/jit/ChangeLog:
	* Make-lang.in: Handle Darwin rpaths.

libatomic/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libbacktrace/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libcc1/ChangeLog:

	* configure: Regenerate.

libffi/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libgcc/ChangeLog:

	* config/t-slibgcc-darwin: Generate libgcc_s
	with an @rpath name.
	* config.host: Handle Darwin rpaths.

libgfortran/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths

libgm2/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* aclocal.m4: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.
	* libm2cor/Makefile.am: Handle Darwin rpaths.
	* libm2cor/Makefile.in: Regenerate.
	* libm2iso/Makefile.am: Handle Darwin rpaths.
	* libm2iso/Makefile.in: Regenerate.
	* libm2log/Makefile.am: Handle Darwin rpaths.
	* libm2log/Makefile.in: Regenerate.
	* libm2min/Makefile.am: Handle Darwin rpaths.
	* libm2min/Makefile.in: Regenerate.
	* libm2pim/Makefile.am: Handle Darwin rpaths.
	* libm2pim/Makefile.in: Regenerate.

libgomp/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths

libitm/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libobjc/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libphobos/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.
	* libdruntime/Makefile.am: Handle Darwin rpaths.
	* libdruntime/Makefile.in: Regenerate.
	* src/Makefile.am: Handle Darwin rpaths.
	* src/Makefile.in: Regenerate.

libquadmath/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libsanitizer/ChangeLog:

	* asan/Makefile.am: Handle Darwin rpaths.
	* asan/Makefile.in: Regenerate.
	* configure: Regenerate.
	* hwasan/Makefile.am: Handle Darwin rpaths.
	* hwasan/Makefile.in: Regenerate.
	* lsan/Makefile.am: Handle Darwin rpaths.
	* lsan/Makefile.in: Regenerate.
	* tsan/Makefile.am: Handle Darwin rpaths.
	* tsan/Makefile.in: Regenerate.
	* ubsan/Makefile.am: Handle Darwin rpaths.
	* ubsan/Makefile.in: Regenerate.

libssp/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libstdc++-v3/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.
	* src/Makefile.am: Handle Darwin rpaths.
	* src/Makefile.in: Regenerate.

libvtv/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

lto-plugin/ChangeLog:
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

zlib/ChangeLog:
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

4 files changed, 226 insertions, 7 deletions

diff --git a/libquadmath/Makefile.am b/libquadmath/Makefile.am
index 35dffb46..0d02c95 100644
--- a/libquadmath/Makefile.am
+++ b/libquadmath/Makefile.am
@@ -36,8 +36,13 @@ endif
 
 toolexeclib_LTLIBRARIES = libquadmath.la
 libquadmath_la_LIBADD = 
+
+if ENABLE_DARWIN_AT_RPATH
+libquadmath_darwin_rpath = -Wc,-nodefaultrpaths
+libquadmath_darwin_rpath += -Wl,-rpath,@loader_path
+endif
 libquadmath_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
-			 $(version_arg) $(lt_host_flags) -lm
+	$(version_arg) $(lt_host_flags) $(LIBM) $(libquadmath_darwin_rpath)
 libquadmath_la_DEPENDENCIES = $(version_dep) $(libquadmath_la_LIBADD)
 
 nodist_libsubinclude_HEADERS = quadmath.h quadmath_weak.h
diff --git a/libquadmath/Makefile.in b/libquadmath/Makefile.in
index 8c01121..068af55 100644
--- a/libquadmath/Makefile.in
+++ b/libquadmath/Makefile.in
@@ -355,6 +355,7 @@ INSTALL_SCRIPT = @INSTALL_SCRIPT@
 INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
 LD = @LD@
 LDFLAGS = @LDFLAGS@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBS = @LIBS@
 LIBTOOL = @LIBTOOL@
@@ -463,8 +464,10 @@ AUTOMAKE_OPTIONS = foreign info-in-builddir
 @BUILD_LIBQUADMATH_TRUE@@LIBQUAD_USE_SYMVER_SUN_TRUE@@LIBQUAD_USE_SYMVER_TRUE@version_dep = quadmath.map-sun
 @BUILD_LIBQUADMATH_TRUE@toolexeclib_LTLIBRARIES = libquadmath.la
 @BUILD_LIBQUADMATH_TRUE@libquadmath_la_LIBADD = 
+@BUILD_LIBQUADMATH_TRUE@@ENABLE_DARWIN_AT_RPATH_TRUE@libquadmath_darwin_rpath = -Wc,-nodefaultrpaths \
+@BUILD_LIBQUADMATH_TRUE@@ENABLE_DARWIN_AT_RPATH_TRUE@	-Wl,-rpath,@loader_path
 @BUILD_LIBQUADMATH_TRUE@libquadmath_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
-@BUILD_LIBQUADMATH_TRUE@			 $(version_arg) $(lt_host_flags) -lm
+@BUILD_LIBQUADMATH_TRUE@	$(version_arg) $(lt_host_flags) $(LIBM) $(libquadmath_darwin_rpath)
 
 @BUILD_LIBQUADMATH_TRUE@libquadmath_la_DEPENDENCIES = $(version_dep) $(libquadmath_la_LIBADD)
 @BUILD_LIBQUADMATH_TRUE@nodist_libsubinclude_HEADERS = quadmath.h quadmath_weak.h
diff --git a/libquadmath/configure b/libquadmath/configure
index 0b145a6..5bd9a07 100755
--- a/libquadmath/configure
+++ b/libquadmath/configure
@@ -644,11 +644,14 @@ LIBQUAD_USE_SYMVER_GNU_FALSE
 LIBQUAD_USE_SYMVER_GNU_TRUE
 LIBQUAD_USE_SYMVER_FALSE
 LIBQUAD_USE_SYMVER_TRUE
+LIBM
 toolexeclibdir
 toolexecdir
 MAINT
 MAINTAINER_MODE_FALSE
 MAINTAINER_MODE_TRUE
+ENABLE_DARWIN_AT_RPATH_FALSE
+ENABLE_DARWIN_AT_RPATH_TRUE
 enable_static
 enable_shared
 lt_host_flags
@@ -785,6 +788,7 @@ with_pic
 enable_fast_install
 with_gnu_ld
 enable_libtool_lock
+enable_darwin_at_rpath
 enable_maintainer_mode
 with_toolexeclibdir
 enable_symvers
@@ -1435,6 +1439,9 @@ Optional Features:
   --enable-fast-install[=PKGS]
                           optimize for fast installation [default=yes]
   --disable-libtool-lock  avoid locking (might break parallel builds)
+  --enable-darwin-at-rpath
+                          install libraries with @rpath/library-name, requires
+                          rpaths to be added to executables
   --enable-maintainer-mode
                           enable make rules and dependencies not useful (and
                           sometimes confusing) to the casual installer
@@ -7310,7 +7317,7 @@ $as_echo "$lt_cv_ld_force_load" >&6; }
       # darwin 5.x (macOS 10.1) onwards we only need to adjust when the
       # deployment target is forced to an earlier version.
       case ${MACOSX_DEPLOYMENT_TARGET-UNSET},$host in
-	UNSET,*-darwin[89]*|UNSET,*-darwin[12][0123456789]*)
+	UNSET,*-darwin[89]*|UNSET,*-darwin[12][0-9]*)
 	  ;;
 	10.[012][,.]*)
 	  _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress'
@@ -9022,6 +9029,49 @@ if test -z "$aix_libpath"; then aix_libpath="/usr/lib:/lib"; fi
     darwin* | rhapsody*)
 
 
+
+  # Publish an arg to allow the user to select that Darwin host (and target)
+  # libraries should be given install-names like @rpath/libfoo.dylib.  This
+  # requires that the user of the library then adds an 'rpath' to the DSO that
+  # needs access.
+  # NOTE: there are defaults below, for systems that support rpaths.  The person
+  # configuring can override the defaults for any system version that supports
+  # them - they are, however, forced off for system versions without support.
+  # Check whether --enable-darwin-at-rpath was given.
+if test "${enable_darwin_at_rpath+set}" = set; then :
+  enableval=$enable_darwin_at_rpath; if test "x$enable_darwin_at_rpath" = "xyes"; then
+    # This is not supported before macOS 10.5 / Darwin9.
+    case ${MACOSX_DEPLOYMENT_TARGET-UNSET},$host_os in
+      UNSET,darwin[4-8]*|UNSET,rhapsody*|10.[0-4][,.]*)
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Darwin @rpath library names are incompatible with OSX versions earlier than 10.5 (rpaths disabled)" >&5
+$as_echo "$as_me: WARNING: Darwin @rpath library names are incompatible with OSX versions earlier than 10.5 (rpaths disabled)" >&2;}
+	enable_darwin_at_rpath=no
+      ;;
+    esac
+   fi
+else
+  case ${MACOSX_DEPLOYMENT_TARGET-UNSET},$host_os in
+    # As above, before 10.5 / Darwin9 this does not work.
+     UNSET,darwin[4-8]*|UNSET,rhapsody*|10.[0-4][,.]*)
+       enable_darwin_at_rpath=no
+       ;;
+
+    # We cannot build and test reliably on macOS 10.11+ (Darwin15+) without use
+    # of rpaths, since runpaths set via DYLD_LIBRARY_PATH are elided by key
+    # system executables (e.g. /bin/sh).  Force rpaths on for these systems.
+      UNSET,darwin1[5-9]*|UNSET,darwin2*|10.1[1-9][,.]*|1[1-9].*[,.]* )
+      { $as_echo "$as_me:${as_lineno-$LINENO}: @rpath library names are needed on macOS versions later than 10.11 (rpaths have been enabled)" >&5
+$as_echo "$as_me: @rpath library names are needed on macOS versions later than 10.11 (rpaths have been enabled)" >&6;}
+      enable_darwin_at_rpath=yes
+      ;;
+    # NOTE: we are not (yet) doing anything for 10.5 .. 10.10, since they can
+    # work with either DYLD_LIBRARY_PATH or embedded rpaths.
+
+    esac
+
+fi
+
+
   archive_cmds_need_lc=no
   hardcode_direct=no
   hardcode_automatic=yes
@@ -9039,9 +9089,13 @@ if test -z "$aix_libpath"; then aix_libpath="/usr/lib:/lib"; fi
   esac
   if test "$_lt_dar_can_shared" = "yes"; then
     output_verbose_link_cmd=func_echo_all
-    archive_cmds="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod${_lt_dsymutil}"
+    _lt_install_name='\$rpath/\$soname'
+    if test "x$enable_darwin_at_rpath" = "xyes"; then
+      _lt_install_name='@rpath/\$soname'
+    fi
+    archive_cmds="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name ${_lt_install_name} \$verstring ${_lt_dsymutil}"
     module_cmds="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dsymutil}"
-    archive_expsym_cmds="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring ${_lt_dar_single_mod}${_lt_dar_export_syms}${_lt_dsymutil}"
+    archive_expsym_cmds="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name ${_lt_install_name} \$verstring ${_lt_dar_export_syms}${_lt_dsymutil}"
     module_expsym_cmds="sed -e 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dar_export_syms}${_lt_dsymutil}"
 
   else
@@ -10868,7 +10922,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 10871 "configure"
+#line 10925 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -10974,7 +11028,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 10977 "configure"
+#line 11031 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11235,6 +11289,14 @@ esac
 
 
 
+ if test x$enable_darwin_at_rpath = xyes; then
+  ENABLE_DARWIN_AT_RPATH_TRUE=
+  ENABLE_DARWIN_AT_RPATH_FALSE='#'
+else
+  ENABLE_DARWIN_AT_RPATH_TRUE='#'
+  ENABLE_DARWIN_AT_RPATH_FALSE=
+fi
+
 
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to enable maintainer-specific portions of Makefiles" >&5
@@ -12199,6 +12261,148 @@ esac
 
 
 
+LIBM=
+case $host in
+*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-haiku* | *-*-pw32* | *-*-darwin*)
+  # These system don't have libm, or don't need it
+  ;;
+*-ncr-sysv4.3*)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _mwvalidcheckl in -lmw" >&5
+$as_echo_n "checking for _mwvalidcheckl in -lmw... " >&6; }
+if ${ac_cv_lib_mw__mwvalidcheckl+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lmw  $LIBS"
+if test x$gcc_no_link = xyes; then
+  as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5
+fi
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char _mwvalidcheckl ();
+int
+main ()
+{
+return _mwvalidcheckl ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_mw__mwvalidcheckl=yes
+else
+  ac_cv_lib_mw__mwvalidcheckl=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_mw__mwvalidcheckl" >&5
+$as_echo "$ac_cv_lib_mw__mwvalidcheckl" >&6; }
+if test "x$ac_cv_lib_mw__mwvalidcheckl" = xyes; then :
+  LIBM="-lmw"
+fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for cos in -lm" >&5
+$as_echo_n "checking for cos in -lm... " >&6; }
+if ${ac_cv_lib_m_cos+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+if test x$gcc_no_link = xyes; then
+  as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5
+fi
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char cos ();
+int
+main ()
+{
+return cos ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_m_cos=yes
+else
+  ac_cv_lib_m_cos=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_cos" >&5
+$as_echo "$ac_cv_lib_m_cos" >&6; }
+if test "x$ac_cv_lib_m_cos" = xyes; then :
+  LIBM="$LIBM -lm"
+fi
+
+  ;;
+*)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for cos in -lm" >&5
+$as_echo_n "checking for cos in -lm... " >&6; }
+if ${ac_cv_lib_m_cos+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+if test x$gcc_no_link = xyes; then
+  as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5
+fi
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char cos ();
+int
+main ()
+{
+return cos ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_m_cos=yes
+else
+  ac_cv_lib_m_cos=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_cos" >&5
+$as_echo "$ac_cv_lib_m_cos" >&6; }
+if test "x$ac_cv_lib_m_cos" = xyes; then :
+  LIBM="-lm"
+fi
+
+  ;;
+esac
+
+
+
 for ac_header in fenv.h langinfo.h locale.h wchar.h wctype.h limits.h ctype.h printf.h errno.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@@ -13459,6 +13663,10 @@ if test -z "${BUILD_INFO_TRUE}" && test -z "${BUILD_INFO_FALSE}"; then
   as_fn_error $? "conditional \"BUILD_INFO\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${ENABLE_DARWIN_AT_RPATH_TRUE}" && test -z "${ENABLE_DARWIN_AT_RPATH_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_DARWIN_AT_RPATH\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${MAINTAINER_MODE_TRUE}" && test -z "${MAINTAINER_MODE_FALSE}"; then
   as_fn_error $? "conditional \"MAINTAINER_MODE\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
diff --git a/libquadmath/configure.ac b/libquadmath/configure.ac
index eec4084..94a3f21 100644
--- a/libquadmath/configure.ac
+++ b/libquadmath/configure.ac
@@ -59,6 +59,7 @@ AM_PROG_LIBTOOL
 ACX_LT_HOST_FLAGS
 AC_SUBST(enable_shared)
 AC_SUBST(enable_static)
+AM_CONDITIONAL([ENABLE_DARWIN_AT_RPATH], [test x$enable_darwin_at_rpath = xyes])
 
 AM_MAINTAINER_MODE
 
@@ -121,6 +122,8 @@ esac
 AC_SUBST(toolexecdir)
 AC_SUBST(toolexeclibdir)
 
+AC_CHECK_LIBM
+
 AC_CHECK_HEADERS(fenv.h langinfo.h locale.h wchar.h wctype.h limits.h ctype.h printf.h errno.h)
 LIBQUAD_CHECK_MATH_H_SIGNGAM