Bug: https://bugs.gentoo.org/776976
Upstream-ML: https://lists.gnu.org/archive/html/libffcall/2022-07/msg00000.html

From: orbea <orbea@riseup.net>
Date: Wed, 13 Jul 2022 17:45:05 -0700
Subject: [PATCH] build: Fix the build with slibtool

Using symlinks to create dummy .lo files does not work with slibtool
which tries to find the corresponding .o file which doesn't exist.

Its better to use the real .lo file instead.
--- a/Makefile.in
+++ b/Makefile.in
@@ -2,6 +2,8 @@
 
 #### Start of system configuration section. ####
 
+CPU = @HOST_CPU_C_ABI@
+
 # Directories used by "make":
 srcdir = @srcdir@
 
@@ -69,8 +71,8 @@ ffcall-version.h : $(srcdir)/ffcall-version.in.h
 ffcall-version.lo : $(srcdir)/ffcall-version.c ffcall-version.h config.h
 	$(LIBTOOL_COMPILE) $(CC) $(CFLAGS) $(CFLAGS) $(INCLUDES) $(CPPFLAGS) $(CFLAGS) -c $(srcdir)/ffcall-version.c
 
-libffcall.la : ffcall-version.lo avcall/avcall.lo avcall/avcall-libapi.lo avcall/avcall-structcpy.lo callback/vacall_r/libvacall.la callback/trampoline_r/libtrampoline.la callback/callback-libapi.lo
-	$(LIBTOOL_LINK) $(CC) $(CFLAGS) $(CFLAGS) -o libffcall.la -rpath $(libdir) -no-undefined -export-symbols-regex $(LIBFFCALL_EXPORTED_SYMBOLS_REGEX) -version-info $(LIBFFCALL_VERSION_INFO) ffcall-version.lo avcall/avcall.lo avcall/avcall-libapi.lo avcall/avcall-structcpy.lo callback/vacall_r/vacall.lo callback/vacall_r/vacall-libapi.lo callback/vacall_r/vacall-structcpy.lo callback/trampoline_r/*.lo callback/callback-libapi.lo gnulib-lib/libgnu.la $(LDFLAGS) $(LTLIBTHREAD)
+libffcall.la : ffcall-version.lo avcall/avcall-$(CPU).lo avcall/avcall-libapi.lo avcall/avcall-structcpy.lo callback/vacall_r/libvacall.la callback/trampoline_r/libtrampoline.la callback/callback-libapi.lo
+	$(LIBTOOL_LINK) $(CC) $(CFLAGS) $(CFLAGS) -o libffcall.la -rpath $(libdir) -no-undefined -export-symbols-regex $(LIBFFCALL_EXPORTED_SYMBOLS_REGEX) -version-info $(LIBFFCALL_VERSION_INFO) ffcall-version.lo avcall/avcall-$(CPU).lo avcall/avcall-libapi.lo avcall/avcall-structcpy.lo callback/vacall_r/vacall-$(CPU).lo callback/vacall_r/vacall-libapi.lo callback/vacall_r/vacall-structcpy.lo callback/trampoline_r/*.lo callback/callback-libapi.lo gnulib-lib/libgnu.la $(LDFLAGS) $(LTLIBTHREAD)
 
 install : force
 	mkdir -p $(DESTDIR)$(prefix)
--- a/avcall/Makefile.in
+++ b/avcall/Makefile.in
@@ -58,7 +58,7 @@ SHELL = /bin/sh
 # Needed by $(LIBTOOL).
 top_builddir = ..
 
-OBJECTS = avcall.lo avcall-libapi.lo avcall-structcpy.lo avcall-compat.lo
+OBJECTS = avcall-$(CPU).lo avcall-libapi.lo avcall-structcpy.lo avcall-compat.lo
 
 # Limit the set of exported symbols, on those platforms where libtool supports it.
 # Currently this does not exclude any symbol; maybe sometime in the future...
@@ -70,11 +70,6 @@ LIBAVCALL_VERSION_INFO = 2:0:1
 
 all : $(OBJECTS) libavcall.la $(srcdir)/avcall.3 $(srcdir)/avcall.html
 
-avcall.lo : avcall-$(CPU).lo
-	$(RM) avcall.lo avcall.@OBJEXT@
-	$(LN) avcall-$(CPU).lo avcall.lo
-	if test -f avcall-$(CPU).@OBJEXT@; then $(LN) avcall-$(CPU).@OBJEXT@ avcall.@OBJEXT@; fi
-
 @IFNOT_MSVC@avcall-i386.lo : avcall-i386.s
 @IFNOT_MSVC@	$(LIBTOOL_COMPILE) $(CC) $(CFLAGS) @GCC_X_NONE@ -c avcall-i386.s
 
--- a/callback/Makefile.in
+++ b/callback/Makefile.in
@@ -77,7 +77,7 @@ callback-compat.lo : $(srcdir)/callback-compat.c ../config.h
 	$(LIBTOOL_COMPILE) $(CC) $(CFLAGS) $(INCLUDES) $(CPPFLAGS) $(CFLAGS) -c $(srcdir)/callback-compat.c
 
 libcallback.la : vacall_r/libvacall.la trampoline_r/libtrampoline.la callback-libapi.lo callback-compat.lo
-	$(LIBTOOL_LINK) $(CC) $(CFLAGS) -o libcallback.la -rpath $(libdir) -no-undefined -export-symbols-regex $(LIBCALLBACK_EXPORTED_SYMBOLS_REGEX) -version-info $(LIBCALLBACK_VERSION_INFO) vacall_r/vacall.lo vacall_r/vacall-libapi.lo vacall_r/vacall-structcpy.lo trampoline_r/*.lo callback-libapi.lo callback-compat.lo ../gnulib-lib/libgnu.la $(LDFLAGS) $(LTLIBTHREAD)
+	$(LIBTOOL_LINK) $(CC) $(CFLAGS) -o libcallback.la -rpath $(libdir) -no-undefined -export-symbols-regex $(LIBCALLBACK_EXPORTED_SYMBOLS_REGEX) -version-info $(LIBCALLBACK_VERSION_INFO) vacall_r/vacall-$(CPU).lo vacall_r/vacall-libapi.lo vacall_r/vacall-structcpy.lo trampoline_r/*.lo callback-libapi.lo callback-compat.lo ../gnulib-lib/libgnu.la $(LDFLAGS) $(LTLIBTHREAD)
 
 # Installs the library and include files only. Typically called with only
 # $(libdir) and $(includedir) - don't use $(prefix) and $(exec_prefix) here.
--- a/callback/vacall_r/Makefile.in
+++ b/callback/vacall_r/Makefile.in
@@ -54,15 +54,10 @@ SHELL = /bin/sh
 # Needed by $(LIBTOOL).
 top_builddir = ../..
 
-OBJECTS = vacall.lo vacall-libapi.lo vacall-structcpy.lo
+OBJECTS = vacall-$(CPU).lo vacall-libapi.lo vacall-structcpy.lo
 
 all : $(OBJECTS) libvacall.la
 
-vacall.lo : vacall-$(CPU).lo
-	$(RM) vacall.lo vacall.@OBJEXT@
-	$(LN) vacall-$(CPU).lo vacall.lo
-	if test -f vacall-$(CPU).@OBJEXT@; then $(LN) vacall-$(CPU).@OBJEXT@ vacall.@OBJEXT@; fi
-
 @IFNOT_MSVC@vacall-i386.lo : vacall-i386.s
 @IFNOT_MSVC@	$(LIBTOOL_COMPILE) $(CC) $(CFLAGS) @GCC_X_NONE@ -c vacall-i386.s