[goffice] win32: build fix from #52

[Morten Welinder <mortenw src gnome org>]

commit 8e65d88e232f1333c72b1ca73b97144643775fac
Author: Morten Welinder <terra gnome org>
Date:   Mon Jan 18 12:42:57 2021 -0500

    win32: build fix from #52

 goffice/Makefile.am | 11 ++++++++++-
 goffice/goffice.h   |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/goffice/Makefile.am b/goffice/Makefile.am
index 08090b169..357ffcb43 100644
--- a/goffice/Makefile.am
+++ b/goffice/Makefile.am
@@ -569,7 +569,16 @@ LIB_PUBLIC_HDRS = $(libgoffice_@GOFFICE_API_VER@_la_HEADERS)
 
 
 goffice.def: $(ALL_HDRS) $(top_srcdir)/tools/dumpdef.pl
-       cat $(top_builddir)/goffice/goffice-config.h $(ALL_HDRS) | \
+       hdrs='$(ALL_HDRS)'; \
+       hdrs_list=''; \
+       for hdr in $$hdrs; do \
+         if test -f $(srcdir)/$$hdr; then \
+           hdrs_list="$$hdrs_list $(srcdir)/$$hdr"; \
+         else \
+           hdrs_list="$$hdrs_list $$hdr"; \
+         fi; \
+       done; \
+       cat $(top_builddir)/goffice/goffice-config.h $$hdrs_list | \
        sed -e 's/^#[   ]*include[      ]\+.*$$//g' | \
        $(CPP) $(AM_CPPFLAGS) "-DGO_VAR_DECL=__declspec(dllexport)" -P - > xgen-localdef.1
        @PERL@ $(top_srcdir)/tools/dumpdef.pl \
diff --git a/goffice/goffice.h b/goffice/goffice.h
index 8f536a5b2..71d81254c 100644
--- a/goffice/goffice.h
+++ b/goffice/goffice.h
@@ -35,7 +35,7 @@
 #ifndef GO_VAR_DECL
 #  ifdef WIN32
 #    ifdef GOFFICE_COMPILATION
-#      define GO_VAR_DECL __declspec(dllexport)
+#      define GO_VAR_DECL extern __declspec(dllexport)
 #    else
 #      define GO_VAR_DECL extern __declspec(dllimport)
 #    endif