cross-build issue in util

Taylor R. Campbell fixed a cross-compilation problem in pkgsrc with a patch for util/Makefile.in. I don't know the proper solution for util/Makefile.am, so I'll cite his explanation and the patch here and hope someone can fix this properly.

Description: The rules to build the makestrs tool go through libtool, which goes through the wrong wrappers as if for cross-compiling, which is wrong for a tool that is run during the build. In practice, this manifests as a PIE linking failure: the .o file was built without -fPIE, but the wrapper causes linker to be invoked with -pie. Just use CC_FOR_BUILD directly to avoid this.

Patch:

--- util/Makefile.in.orig       2021-01-24 14:47:52.000000000 +0000
+++ util/Makefile.in
@@ -394,7 +394,11 @@ clean-noinstPROGRAMS:
 
 makestrs$(EXEEXT): $(makestrs_OBJECTS) $(makestrs_DEPENDENCIES) $(EXTRA_makestrs_DEPENDENCIES) 
        @rm -f makestrs$(EXEEXT)
-       $(AM_V_CCLD)$(LINK) $(makestrs_OBJECTS) $(makestrs_LDADD) $(LIBS)
+       $(AM_V_CCLD)$(CC_FOR_BUILD) $(CFLAGS_FOR_BUILD) $(LDFLAGS_FOR_BUILD) -o $@ $(makestrs_OBJECTS) $(LIBS_FOR_BUILD)
+
+makestrs.$(OBJEXT): makestrs.c
+       $(AM_V_CC)$(CC_FOR_BUILD) $(CFLAGS_FOR_BUILD) $(CPPFLAGS_FOR_BUILD) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
+       $(AM_V_at)$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Po
 
 mostlyclean-compile:
        -rm -f *.$(OBJEXT)