Fix gdbsupport build

I'm seeing this on F27 (a clean build from scratch):

~~~~~~~~~~~~~~~~~~~~~~~~~~~
 make[3]: Entering directory '/home/pedro/brno/pedro/gdb/binutils-gdb/build/gdbsupport'
   CC       gdb_tilde_expand.o
 In file included from /home/pedro/gdb/binutils-gdb/src/gdbsupport/../gnulib/import/libc-config.h:33:0,
                  from ../gnulib/import/glob.h:544,
                  from /home/pedro/gdb/binutils-gdb/src/gdbsupport/gdb_tilde_expand.c:22:
 ../bfd/config.h:7:4: error: #error config.h must be #included before system headers
  #  error config.h must be #included before system headers
     ^~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~

libc-config.h, where it includes config.h, says:

~~~~~~~~~~~~~~~~~~~~~~~~~~~
 /* This is intended to be a good-enough substitute for glibc system
    macros like those defined in <sys/cdefs.h>, so that Gnulib code
    shared with glibc can do this as the first #include:

      #ifndef _LIBC
      # include <libc-config.h>
      #endif

    When compiled as part of glibc this is a no-op; when compiled as
    part of Gnulib this includes Gnulib's <config.h> and defines macros
    that glibc library code would normally assume.  */

 #include <config.h>
~~~~~~~~~~~~~~~~~~~~~~~~~~~

The issue is that that '#include <config.h>' picks up bfd's config.h
instead of gnulib's.

This problem doesn't trigger in the gdb dir because there we generate
config.h under that exact name so gnulib's libc-config.h ends up
picking gdb's config.h instead of gnulib.c and that ends up harmless.

In gdbsupport, the config.h file is really named support-config.h, so
that '#include <config.h>' in libc-config.h doesn't pick it like it
would if it had the conventional config.h name.

This patch fixes it by simply renaming gdbserver's support-config.h to
config.h.

gdbsupport/ChangeLog:
2020-01-17  Pedro Alves  <palves@redhat.com>

	* configure.ac: Generate config.h instead of support-config.h.
	* common-defs.h: Include <gdbsupport/config.h> instead of
	<gdbsupport/support-config.h>.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

gdbsupport/ChangeLog

@@ -1,3 +1,11 @@
+2020-01-17  Pedro Alves  <palves@redhat.com>
+
+	* configure.ac: Generate config.h instead of support-config.h.
+	* common-defs.h: Include <gdbsupport/config.h> instead of
+	<gdbsupport/support-config.h>.
+	* Makefile.in: Regenerate.
+	* configure: Regenerate.
+
 2020-01-14  Tom Tromey  <tom@tromey.com>
 
 	* Makefile.in: Rebuild.

gdbsupport/Makefile.in

@@ -132,7 +132,7 @@ DIST_COMMON = $(srcdir)/Makefile.am $(top_srcdir)/configure \
 am__CONFIG_DISTCLEAN_FILES = config.status config.cache config.log \
  configure.lineno config.status.lineno
 mkinstalldirs = $(SHELL) $(top_srcdir)/../mkinstalldirs
-CONFIG_HEADER = support-config.h
+CONFIG_HEADER = config.h
 CONFIG_CLEAN_FILES =
 CONFIG_CLEAN_VPATH_FILES =
 LIBRARIES = $(noinst_LIBRARIES)
@@ -388,7 +388,7 @@ libgdbsupport_a_SOURCES = \
     xml-utils.c	\
     $(selftest)
 
-all: support-config.h
+all: config.h
 	$(MAKE) $(AM_MAKEFLAGS) all-am
 
 .SUFFIXES:
@@ -427,20 +427,20 @@ $(ACLOCAL_M4): @MAINTAINER_MODE_TRUE@ $(am__aclocal_m4_deps)
 	$(am__cd) $(srcdir) && $(ACLOCAL) $(ACLOCAL_AMFLAGS)
 $(am__aclocal_m4_deps):
 
-support-config.h: stamp-h1
+config.h: stamp-h1
 	@test -f $@ || rm -f stamp-h1
 	@test -f $@ || $(MAKE) $(AM_MAKEFLAGS) stamp-h1
 
 stamp-h1: $(srcdir)/config.in $(top_builddir)/config.status
 	@rm -f stamp-h1
-	cd $(top_builddir) && $(SHELL) ./config.status support-config.h
+	cd $(top_builddir) && $(SHELL) ./config.status config.h
 $(srcdir)/config.in: @MAINTAINER_MODE_TRUE@ $(am__configure_deps) 
 	($(am__cd) $(top_srcdir) && $(AUTOHEADER))
 	rm -f stamp-h1
 	touch $@
 
 distclean-hdr:
-	-rm -f support-config.h stamp-h1
+	-rm -f config.h stamp-h1
 
 clean-noinstLIBRARIES:
 	-test -z "$(noinst_LIBRARIES)" || rm -f $(noinst_LIBRARIES)
@@ -565,7 +565,7 @@ distclean-tags:
 	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
 check-am: all-am
 check: check-am
-all-am: Makefile $(LIBRARIES) support-config.h
+all-am: Makefile $(LIBRARIES) config.h
 installdirs:
 install: install-am
 install-exec: install-exec-am

gdbsupport/common-defs.h

@@ -34,7 +34,7 @@
 
 #else  /* GDBSERVER */
 
-#include <gdbsupport/support-config.h>
+#include <gdbsupport/config.h>
 
 #undef PACKAGE_NAME
 #undef PACKAGE

gdbsupport/configure

@@ -2713,7 +2713,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-ac_config_headers="$ac_config_headers support-config.h:config.in"
+ac_config_headers="$ac_config_headers config.h:config.in"
 
 ac_aux_dir=
 for ac_dir in "$srcdir" "$srcdir/.." "$srcdir/../.."; do
@@ -11563,7 +11563,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 for ac_config_target in $ac_config_targets
 do
   case $ac_config_target in
-    "support-config.h") CONFIG_HEADERS="$CONFIG_HEADERS support-config.h:config.in" ;;
+    "config.h") CONFIG_HEADERS="$CONFIG_HEADERS config.h:config.in" ;;
     "depfiles") CONFIG_COMMANDS="$CONFIG_COMMANDS depfiles" ;;
     "Makefile") CONFIG_FILES="$CONFIG_FILES Makefile" ;;
 

gdbsupport/configure.ac

@@ -18,7 +18,7 @@ dnl Process this file with autoconf to produce a configure script.
 
 AC_INIT([gdbsupport], 1.0)
 AC_CONFIG_SRCDIR(common-defs.h)
-AC_CONFIG_HEADER(support-config.h:config.in)
+AC_CONFIG_HEADER(config.h:config.in)
 AC_CANONICAL_SYSTEM
 AM_MAINTAINER_MODE
 AC_CONFIG_AUX_DIR(..)