compile: Add 'set compile-gcc'

As discussed in
	How to use compile & execute function in GDB
	https://sourceware.org/ml/gdb/2015-04/msg00026.html

GDB currently searches for compilers on /usr/bin/ARCH-OS-gcc and
chooses a match from there.  However, it is not currently possible for
the user to override which compiler to use.  This is what this patch
implements.

It is also a sync between GCC's and GDB's interfaces.

gdb/ChangeLog
2017-08-23  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* NEWS (Changes since GDB 7.9): Add set compile-gcc and show
	compile-gcc.
	* compile/compile.c (compile_gcc, show_compile_gcc): New.
	(compile_to_object): Implement compile_gcc.
	(_initialize_compile): Install "set compile-gcc".  Initialize
	compile_gcc.

gdb/doc/ChangeLog
2017-08-23  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.texinfo (Compiling and Injecting Code): Add to subsection
	"Compiler search for the compile command" descriptions of set
	compile-gcc and show compile-gcc.

include/ChangeLog
2017-08-23  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gcc-interface.h (enum gcc_base_api_version): Update comment for
	GCC_FE_VERSION_1.
	(struct gcc_base_vtable): Rename set_arguments to set_arguments_v0.
	Add set_arguments, set_triplet_regexp and set_driver_filename.

2 files changed, 54 insertions, 14 deletions

diff --git a/include/ChangeLog b/include/ChangeLog
index 02ee554..3b89deb 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,5 +1,12 @@
 2017-08-23  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
+	* gcc-interface.h (enum gcc_base_api_version): Update comment for
+	GCC_FE_VERSION_1.
+	(struct gcc_base_vtable): Rename set_arguments to set_arguments_v0.
+	Add set_arguments, set_triplet_regexp and set_driver_filename.
+
+2017-08-23  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
 	* gcc-interface.h (enum gcc_base_api_version): Add
 	GCC_FE_VERSION_1.
 	(struct gcc_base_vtable): Rename compile to compile_v0.  Update
diff --git a/include/gcc-interface.h b/include/gcc-interface.h
index c98f078..e3ffd18 100644
--- a/include/gcc-interface.h
+++ b/include/gcc-interface.h
@@ -46,7 +46,9 @@ enum gcc_base_api_version
 {
   GCC_FE_VERSION_0 = 0,
 
-  /* Deprecated method compile_v0.  Added method set_verbose and compile.  */
+  /* Deprecated methods set_arguments_v0 and compile_v0.  Added methods
+     set_arguments, set_triplet_regexp, set_driver_filename, set_verbose and
+     compile.  */
   GCC_FE_VERSION_1 = 1,
 };
 
@@ -67,20 +69,12 @@ struct gcc_base_vtable
 
   unsigned int version;
 
-  /* Set the compiler's command-line options for the next compilation.
-     TRIPLET_REGEXP is a regular expression that is used to match the
-     configury triplet prefix to the compiler.
-     The arguments are copied by GCC.  ARGV need not be
-     NULL-terminated.  The arguments must be set separately for each
-     compilation; that is, after a compile is requested, the
-     previously-set arguments cannot be reused.
-
-     This returns NULL on success.  On failure, returns a malloc()d
-     error message.  The caller is responsible for freeing it.  */
+  /* Deprecated GCC_FE_VERSION_0 variant of the GCC_FE_VERSION_1
+     methods set_triplet_regexp and set_arguments.  */
 
-  char *(*set_arguments) (struct gcc_base_context *self,
-			  const char *triplet_regexp,
-			  int argc, char **argv);
+  char *(*set_arguments_v0) (struct gcc_base_context *self,
+			     const char *triplet_regexp,
+			     int argc, char **argv);
 
   /* Set the file name of the program to compile.  The string is
      copied by the method implementation, but the caller must
@@ -125,6 +119,45 @@ struct gcc_base_vtable
 
   int /* bool */ (*compile) (struct gcc_base_context *self,
 			     const char *filename);
+
+  /* Set the compiler's command-line options for the next compilation.
+     The arguments are copied by GCC.  ARGV need not be
+     NULL-terminated.  The arguments must be set separately for each
+     compilation; that is, after a compile is requested, the
+     previously-set arguments cannot be reused.
+
+     This returns NULL on success.  On failure, returns a malloc()d
+     error message.  The caller is responsible for freeing it.
+
+     This method is only available since GCC_FE_VERSION_1.  */
+
+  char *(*set_arguments) (struct gcc_base_context *self,
+			  int argc, char **argv);
+
+  /* Set TRIPLET_REGEXP as a regular expression that is used to match
+     the configury triplet prefix to the compiler.  Calling this method
+     overrides possible previous call of itself or set_driver_filename.
+
+     This returns NULL on success.  On failure, returns a malloc()d
+     error message.  The caller is responsible for freeing it.
+
+     This method is only available since GCC_FE_VERSION_1.  */
+
+  char *(*set_triplet_regexp) (struct gcc_base_context *self,
+			       const char *triplet_regexp);
+
+  /* DRIVER_FILENAME should be filename of the gcc compiler driver
+     program.  It will be searched in PATH components like
+     TRIPLET_REGEXP.  Calling this method overrides possible previous
+     call of itself or set_triplet_regexp.
+
+     This returns NULL on success.  On failure, returns a malloc()d
+     error message.  The caller is responsible for freeing it.
+
+     This method is only available since GCC_FE_VERSION_1.  */
+
+  char *(*set_driver_filename) (struct gcc_base_context *self,
+				const char *driver_filename);
 };
 
 /* The GCC object.  */