I've finally found a way (quite accidentally) to add linker flags when
compiling genbc. Modifing grammar file did not work for me either (to
heavy code modification without proper understanding of how the vm is
built). And requesting a linker to accept having multiple definition is
acceptable since genbc impl and decl parsers dont work at the same time.
diff --git a/libgst/Makefile.am b/libgst/Makefile.am
index 8841ea4c..82198e8f 100644
--- a/libgst/Makefile.am
+++ b/libgst/Makefile.am
@@ -50,7 +50,8 @@ genprims_LDADD = @LIBSNPRINTFV@
$(top_builddir)/lib-src/library.la
genbc_SOURCES = \
genbc-decl.y genbc-impl.y genbc-scan.l genbc.c
-genbc_LDADD = @LIBSNPRINTFV@ $(top_builddir)/lib-src/library.la
+genbc_LDADD = @LIBSNPRINTFV@ $(top_builddir)/lib-src/library.la
+genbc_LDFLAGS = -Wl,-allow-multiple-definition
# definitions for genvm
