libgcc, X86, Darwin: Handle symbols for HF cases.

This reorganises the Darwin symbol vers files to include
the generic ones at the top level; allowing for arch ports
to override (via either exclusion or inclusion as needed).

We add an X86-specific vers file containing the new HF
symbols.  Note that although Darwin does not use ELF-style
symbol versioning - the parser that produces the map can
consume it.  Using the ELF-style description will help us
know at which rev the symbols were introduced.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

libgcc/ChangeLog:

	* config/i386/t-darwin: Add in a vers file for X86-specific
	symbols.
	* config/t-darwin: Add the generic symbol maps here...
	* config/t-slibgcc-darwin: ... removing from here.
	* config/i386/libgcc-darwin.ver: New file.

libgcc/config/i386/libgcc-darwin.ver

+
+
+%inherit GCC_12.0.0 GCC_7.0.0
+GCC_12.0.0 {
+  __divhc3
+  __mulhc3
+  __eqhf2
+  __nehf2
+  __extendhfdf2
+  __extendhfsf2
+  __extendhftf2
+  __extendhfxf2
+  __fixhfti
+  __fixunshfti
+  __floattihf
+  __floatuntihf
+  __truncdfhf2
+  __truncsfhf2
+  __trunctfhf2
+  __truncxfhf2
+}

libgcc/config/i386/t-darwin

 LIB2_SIDITI_CONV_FUNCS = yes
 LIB2ADD = $(srcdir)/config/darwin-64.c
 LIB2FUNCS_EXCLUDE = _fixtfdi _fixunstfdi _floatditf _floatunditf
+
+# Extra symbols for this port.
+SHLIB_MAPFILES += $(srcdir)/config/i386/libgcc-darwin.ver

libgcc/config/t-darwin

@@ -24,3 +24,6 @@ d10-uwfef.o: $(srcdir)/config/darwin10-unwind-find-enc-func.c
 libd10-uwfef.a: d10-uwfef.o
 	$(AR_CREATE_FOR_TARGET) $@ d10-uwfef.o
 	$(RANLIB_FOR_TARGET) $@
+
+# Symbols for all the sub-ports.
+SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/libgcc-libsystem.ver

libgcc/config/t-slibgcc-darwin

@@ -24,7 +24,6 @@ SHLIB_LINK = $(CC) $(LIBGCC2_CFLAGS) $(LDFLAGS) -dynamiclib -nodefaultlibs \
 
 SHLIB_MKMAP = $(srcdir)/mkmap-flat.awk
 SHLIB_MKMAP_OPTS = -v leading_underscore=1
-SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/libgcc-libsystem.ver
 SHLIB_VERPFX = $(srcdir)/config/$(cpu_type)/libgcc-darwin
 
 # we're only going to build the stubs if the target slib is /usr/lib