[newlib-cygwin] newlib: fix multilib libg.a parallel builds

[newlib-cygwin] newlib: fix multilib libg.a parallel builds

[Michael Frysinger]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=acf642177b81543a4d954e58cfb24347c02b125a

commit acf642177b81543a4d954e58cfb24347c02b125a
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Wed Feb 23 22:01:05 2022 -0500

    newlib: fix multilib libg.a parallel builds
    
    I split libg.a out into a sep target from libc.a for the main dir in
    commit f2b053f49ed2bd7b4da8cf4ed3a608dc2f425c2b ("newlib: separate out
    libg from libc"), but missed the multilib dirs.  That leads to an
    uncommon parallel build failure:
    - libc.a rule runs & finishes
    - $(BUILD_MULTISUBDIR)/libc.a rule runs
      -> failure due to libg.a not yet existing
    - libg.a rule runs & finishes
    
    Split the multilib libg rule out from libc too so it can depend on the
    main libg directly and avoid this race.

Diff:
---
 newlib/Makefile.am | 8 +++++---
 newlib/Makefile.in | 8 +++++---
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/newlib/Makefile.am b/newlib/Makefile.am
index 1a5123f0a..0479ca4f5 100644
--- a/newlib/Makefile.am
+++ b/newlib/Makefile.am
@@ -161,10 +161,12 @@ $(BUILD_MULTISUBDIR)/crt0.o: $(CRT0_DIR)$(CRT0) $(BUILD_MULTISUBDIR)
 	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
 
 $(BUILD_MULTISUBDIR)/libc.a: libc.a $(BUILD_MULTISUBDIR)
-	rm -f $@ $(BUILD_MULTISUBDIR)/libg.a
+	rm -f $@
+	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
+
+$(BUILD_MULTISUBDIR)/libg.a: libg.a ${BUILD_MULTISUBDIR}
+	rm -f $@
 	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
-	ln libg.a $(BUILD_MULTISUBDIR)/libg.a >/dev/null 2>/dev/null || \
-	cp libg.a $(BUILD_MULTISUBDIR)/libg.a
 
 $(BUILD_MULTISUBDIR)/libm.a: libm.a $(BUILD_MULTISUBDIR)
 	rm -f $@
diff --git a/newlib/Makefile.in b/newlib/Makefile.in
index cc7afc704..106f11ba0 100644
--- a/newlib/Makefile.in
+++ b/newlib/Makefile.in
@@ -8672,10 +8672,12 @@ libm.a: $(libm_a_OBJECTS) $(libm_a_DEPENDENCIES)
 @HAVE_MULTISUBDIR_TRUE@	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
 
 @HAVE_MULTISUBDIR_TRUE@$(BUILD_MULTISUBDIR)/libc.a: libc.a $(BUILD_MULTISUBDIR)
-@HAVE_MULTISUBDIR_TRUE@	rm -f $@ $(BUILD_MULTISUBDIR)/libg.a
+@HAVE_MULTISUBDIR_TRUE@	rm -f $@
+@HAVE_MULTISUBDIR_TRUE@	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
+
+@HAVE_MULTISUBDIR_TRUE@$(BUILD_MULTISUBDIR)/libg.a: libg.a ${BUILD_MULTISUBDIR}
+@HAVE_MULTISUBDIR_TRUE@	rm -f $@
 @HAVE_MULTISUBDIR_TRUE@	ln $< $@ >/dev/null 2>/dev/null || cp $< $@
-@HAVE_MULTISUBDIR_TRUE@	ln libg.a $(BUILD_MULTISUBDIR)/libg.a >/dev/null 2>/dev/null || \
-@HAVE_MULTISUBDIR_TRUE@	cp libg.a $(BUILD_MULTISUBDIR)/libg.a
 
 @HAVE_MULTISUBDIR_TRUE@$(BUILD_MULTISUBDIR)/libm.a: libm.a $(BUILD_MULTISUBDIR)
 @HAVE_MULTISUBDIR_TRUE@	rm -f $@