lib/gvpr: compile mkdefs with $(HOSTCC) rather than $(CC)

When cross-compiling graphviz the host tries to run mkdefs to generate
gdefs.h, which then fails with something like:

```
/bin/sh: ./mkdefs: cannot execute binary file: Exec format error
```

To work around this we can introduce a variable $(HOSTCC), which expands
to the standard compiler, `$(CC)`, unless the user has run
`export HOSTCC=some-host-compiler` or similar before configuring.

diff --git a/lib/gvpr/Makefile.am b/lib/gvpr/Makefile.am
index ac3c0980f85ff755146f29b26ab27f474573e7b9..d47752216eba0da1bd82640c252f420c33c6ab1c 100644 (file)
--- a/lib/gvpr/Makefile.am
+++ b/lib/gvpr/Makefile.am
@@ -3,7 +3,7 @@
 
 pdfdir = $(pkgdatadir)/doc/pdf
 pkgconfigdir = $(libdir)/pkgconfig
-
+HOSTCC ?= $(CC)
 GVPR_VERSION="2:0:0"
 
 AM_CPPFLAGS = \
@@ -21,7 +21,6 @@ AM_CPPFLAGS = \
        -DDFLT_GVPRPATH="\".$(PATH_SEPARATOR)$(pkgdatadir)/gvpr\""
 
 pkginclude_HEADERS = gvpr.h
-noinst_PROGRAMS = mkdefs
 noinst_HEADERS = actions.h compile.h gprstate.h parse.h queue.h trieFA.h trie.c
 noinst_LTLIBRARIES = libgvpr_C.la
 lib_LTLIBRARIES = libgvpr.la
@@ -54,7 +53,8 @@ if WITH_WIN32
 libgvpr_la_LDFLAGS += -export-symbols-regex gvpr
 endif
 
-mkdefs_SOURCES = mkdefs.c
+mkdefs$(EXEEXT):
+       $(HOSTCC) $(srcdir)/mkdefs.c -o mkdefs$(EXEEXT)
 
 gdefs.h: $(top_srcdir)/lib/gvpr/gprdata mkdefs$(EXEEXT)
        ./mkdefs$(EXEEXT) gdefs.h < $(top_srcdir)/lib/gvpr/gprdata