Introduce "gdb/configure.nat" (and delete "gdb/config/*/*.mh" files)

Due to my ongoing work to make it possible for gdbserver to start the
inferior using the shell, I had to share the fork_inferior function
under the "nat/" directory.  In order to do that, I created a new file
and put the function there; however, this meant that I now had to
update some of the *.mh files (under "gdb/config") and add the new
file as a dependency to be built natively.  Bleh...

After talking a bit to Pedro about this, the idea came up to write a
new "gdb/configure.nat" file, a la "gdb/configure.tgt", which would
concentrate all of the native settings for each host/system.  I
decided to tackle this issue.

The patch is simple.  All of the previous Makefile variables that were
being declared inside the *.mh files are now inside "gdb/Makefile.in",
and "gdb/configure" is responsible for AC_SUBST'ing them.  The
definitions of these variables were put inside "gdb/configure.nat", so
now they're shell variables.  For excerpts of Makefile code, one must
create a file under "gdb/config/${gdb_cpu_host}" and reference it on
the "nat_extra_makefile_frag" variable.

It should now be easier to update the native dependencies of hosts in
this single file.

This has been tested on x86_64 without regressions.

gdb/ChangeLog:
2017-05-06  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in: Remove "@host_makefile_frag@".  Add variables
	NAT_FILE, NATDEPFILES, NAT_CDEPS, LOADLIBES, MH_CFLAGS, XM_CLIBS,
	NAT_GENERATED_FILES, HAVE_NATIVE_GCORE_HOST.  Add
	"@nat_extra_makefile_frag@".
	(Makefile): Remove dependency on "@frags@".
	($(GNULIB_BUILDDIR)/Makefile): Likewise.
	(data-directory/Makefile): Likewise.
	* config/aarch64/linux.mh: Deleted; moved contents to
	"gdb/configure.nat".
	* config/alpha/alpha-linux.mh: Likewise.
	* config/alpha/nbsd.mh: Likewise.
	* config/arm/linux.mh: Likewise.
	* config/arm/nbsdelf.mh: Likewise.
	* config/i386/cygwin.mh: Likewise.
	* config/i386/cygwin64.mh: Likewise.
	* config/i386/darwin.mh: Likewise.
	* config/i386/fbsd.mh: Likewise.
	* config/i386/fbsd64.mh: Likewise.
	* config/i386/go32.mh: Likewise.
	* config/i386/i386gnu.mh: Likewise.
	* config/i386/i386sol2.mh: Likewise.
	* config/i386/linux.mh: Likewise.
	* config/i386/linux64.mh: Likewise.
	* config/i386/mingw.mh: Likewise.
	* config/i386/mingw64.mh: Likewise.
	* config/i386/nbsd64.mh: Likewise.
	* config/i386/nbsdelf.mh: Likewise.
	* config/i386/nto.mh: Likewise.
	* config/i386/obsd.mh: Likewise.
	* config/i386/obsd64.mh: Likewise.
	* config/i386/sol2-64.mh: Likewise.
	* config/ia64/linux.mh: Likewise.
	* config/m32r/linux.mh: Likewise.
	* config/m68k/linux.mh: Likewise.
	* config/m68k/nbsdelf.mh: Likewise.
	* config/m68k/obsd.mh: Likewise.
	* config/m88k/obsd.mh: Likewise.
	* config/mips/fbsd.mh: Likewise.
	* config/mips/linux.mh: Likewise.
	* config/mips/nbsd.mh: Likewise.
	* config/mips/obsd64.mh: Likewise.
	* config/pa/linux.mh: Likewise.
	* config/pa/nbsd.mh: Likewise.
	* config/pa/obsd.mh: Likewise.
	* config/powerpc/aix.mh: Likewise.
	* config/powerpc/fbsd.mh: Likewise.
	* config/powerpc/linux.mh: Likewise.
	* config/powerpc/nbsd.mh: Likewise.
	* config/powerpc/obsd.mh: Likewise.
	* config/powerpc/ppc64-linux.mh: Likewise.
	* config/powerpc/spu-linux.mh: Likewise.
	* config/s390/linux.mh: Likewise.
	* config/sh/nbsd.mh: Likewise.
	* config/sparc/fbsd.mh: Likewise.
	* config/sparc/linux.mh: Likewise.
	* config/sparc/linux64.mh: Likewise.
	* config/sparc/nbsd64.mh: Likewise.
	* config/sparc/nbsdelf.mh: Likewise.
	* config/sparc/obsd64.mh: Likewise.
	* config/sparc/sol2.mh: Likewise.
	* config/tilegx/linux.mh: Likewise.
	* config/vax/nbsdelf.mh: Likewise.
	* config/vax/obsd.mh: Likewise.
	* config/xtensa/linux.mh: Likewise.
	* config/i386/i386gnu.mn: New file, with excerpts from
	"config/i386/i386gnu.mh".
	* configure: Regenerate.
	* configure.ac: Rewrite code to use "gdb/configure.nat" instead of
	*.mh files under "gdb/config".
	* configure.nat: New file, with contents from the
	"gdb/config/*/*.mh" files.

gdb/doc/ChangeLog:
2017-05-06  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile: Remove "@host_makefile_frag@".

1 files changed, 18 insertions, 6 deletions

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 2f7d355c6d..70d7d500d1 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -904,9 +904,21 @@ ALL_TARGET_OBS = \
 	xtensa-linux-tdep.o \
 	xtensa-tdep.o
 
-# Host-dependent makefile fragment comes in here.
-@host_makefile_frag@
-# End of host-dependent makefile fragment
+# The following native-target dependent variables are defined on
+# configure.nat.
+NAT_FILE = @NAT_FILE@
+NATDEPFILES = @NATDEPFILES@
+NAT_CDEPS = @NAT_CDEPS@
+LOADLIBES = @LOADLIBES@
+MH_CFLAGS = @MH_CFLAGS@
+XM_CLIBS = @XM_CLIBS@
+NAT_GENERATED_FILES = @NAT_GENERATED_FILES@
+HAVE_NATIVE_GCORE_HOST = @HAVE_NATIVE_GCORE_HOST@
+
+# Native-target dependent makefile fragment comes in here.
+@nat_extra_makefile_frag@
+
+# End of native-target dependent variables.
 
 FLAGS_TO_PASS = \
 	"prefix=$(prefix)" \
@@ -2320,21 +2332,21 @@ subdir_do: force
 		else true ; fi ; \
 	done
 
-Makefile: Makefile.in config.status @frags@
+Makefile: Makefile.in config.status
 	# Regenerate the Makefile and the tm.h / nm.h links.
 	CONFIG_FILES="Makefile" \
 	  CONFIG_COMMANDS= \
 	  CONFIG_HEADERS= \
 	  $(SHELL) config.status
 
-$(GNULIB_BUILDDIR)/Makefile: gnulib/Makefile.in config.status @frags@
+$(GNULIB_BUILDDIR)/Makefile: gnulib/Makefile.in config.status
 	@cd $(GNULIB_BUILDDIR); CONFIG_FILES="Makefile" \
 	  CONFIG_COMMANDS="depfiles" \
 	  CONFIG_HEADERS= \
 	  CONFIG_LINKS= \
 	  $(SHELL) config.status
 
-data-directory/Makefile: data-directory/Makefile.in config.status @frags@
+data-directory/Makefile: data-directory/Makefile.in config.status
 	CONFIG_FILES="data-directory/Makefile" \
 	  CONFIG_COMMANDS="depfiles" \
 	  CONFIG_HEADERS= \