build: Remove superfluous MAKE variable for the build suffix

Use BUILDSUF instead.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -4340,7 +4340,6 @@ ifndef FFMPEG_CONFIG_MAK
 FFMPEG_CONFIG_MAK=1
 FFMPEG_CONFIGURATION=$FFMPEG_CONFIGURATION
 prefix=$prefix
-build_suffix=${build_suffix}
 LIBDIR=\$(DESTDIR)$libdir
 SHLIBDIR=\$(DESTDIR)$shlibdir
 INCDIR=\$(DESTDIR)$incdir

library.mak

@@ -85,7 +85,7 @@ install-lib$(NAME)-headers: $(addprefix $(SUBDIR),$(HEADERS) $(BUILT_HEADERS))
 	$(Q)mkdir -p "$(INCINSTDIR)"
 	$$(INSTALL) -m 644 $$^ "$(INCINSTDIR)"
 
-install-lib$(NAME)-pkgconfig: $(SUBDIR)lib$(NAME)${build_suffix}.pc
+install-lib$(NAME)-pkgconfig: $(SUBDIR)lib$(FULLNAME).pc
 	$(Q)mkdir -p "$(LIBDIR)/pkgconfig"
 	$$(INSTALL) -m 644 $$^ "$(LIBDIR)/pkgconfig"
 
@@ -99,7 +99,7 @@ uninstall-libs::
 
 uninstall-headers::
 	$(RM) $(addprefix "$(INCINSTDIR)/",$(HEADERS) $(BUILT_HEADERS))
-	$(RM) "$(LIBDIR)/pkgconfig/lib$(NAME)${build_suffix}.pc"
+	$(RM) "$(LIBDIR)/pkgconfig/lib$(FULLNAME).pc"
 	-rmdir "$(INCINSTDIR)"
 endef