The FreeBSD sed command doesn't understand \? without passing -E to turn
on extended regexps. This patch changes the DSO_EXPORTS_CMD regexp to a
POSIX compliant RE by switching the \+ to a \{1,\} bound and the \? to a
\{0,1\} bound.
LIB_PATH_VAR=@LIB_PATH_VAR@
## Dynamic shared libraries build settings
-DSO_EXPORTS_CMD=-Wl,--version-script,$(srcdir)/exports/`basename $@ | sed 's/@SHLIBEXT@\(.[0-9]\+\)\?$$/@SYMSEXT@/'`
+DSO_EXPORTS_CMD=-Wl,--version-script,$(srcdir)/exports/`basename $@ | sed 's/@SHLIBEXT@\(.[0-9]\{1,\}\)\{0,1\}$$/@SYMSEXT@/'`
DSO_EXPORTS=@DSO_EXPORTS@
SHLD_DSO = $(SHLD) $(LDSHFLAGS) $(DSO_EXPORTS) -o $@