libstdc++: Stop using _GLIBCXX_USE_C99_COMPLEX_TR1 in <complex>

The _GLIBCXX_USE_C99_COMPLEX_TR1 macro (and the comments about it in
acinclude.m4 and config.h) are misleading when it is also used for
<complex>, not only <tr1/complex>. It is also wrong, because the
configure checks for TR1 use -std=c++98 and a target might define cacos
etc. for C++11 but not for C++98.

Add a separate configure check for the inverse trigonometric functions
that are covered by _GLIBCXX_USE_C99_COMPLEX_TR1, but using -std=c++11
for the checks. Use the result of that separate check in <complex>.

libstdc++-v3/ChangeLog:

	* acinclude.m4 (GLIBCXX_USE_C99): Check for complex inverse trig
	functions in C++11 mode and define _GLIBCXX_USE_C99_COMPLEX_ARC.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* doc/doxygen/user.cfg.in (PREDEFINED): Add new macro.
	* include/std/complex: Check _GLIBCXX_USE_C99_COMPLEX_ARC
	instead of _GLIBCXX_USE_C99_COMPLEX_TR1.

1 files changed, 5 insertions, 0 deletions

diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in
index a336daf..8e037fb 100644
--- a/libstdc++-v3/config.h.in
+++ b/libstdc++-v3/config.h.in
@@ -892,6 +892,11 @@
    <stdio.h>, and <stdlib.h> can be used or exposed. */
 #undef _GLIBCXX_USE_C99
 
+/* Define if C99 inverse trig functions in <complex.h> should be used in
+   <complex>. Using compiler builtins for these functions requires
+   corresponding C99 library functions to be present. */
+#undef _GLIBCXX_USE_C99_COMPLEX_ARC
+
 /* Define if C99 functions in <complex.h> should be used in <tr1/complex>.
    Using compiler builtins for these functions requires corresponding C99
    library functions to be present. */