The regex.c module depends on regex_internal.h, which depends on
intprops.h, which depends on verify.h, which is GPLv3, not LGPL like
the rest of the regex module.
I'm using the equivalent of the patch at the end of this E-Mail to
import the engine into a GPLv2 only project, but this seems like a
general bug in gnulib.
$ git diff -U2
diff --git a/lib/intprops.h b/lib/intprops.h
index c31a455e4..c14c90ea7 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -22,5 +22,7 @@
#include <limits.h>
+#if 0
#include <verify.h>
+#endif
/* Return a value with the common real type of E and V and the value of V. */
@@ -78,4 +80,5 @@
#endif
+#if 0
/* This include file assumes that signed types are two's complement without
padding bits; the above macros have undefined behavior otherwise.
@@ -99,4 +102,5 @@ verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
#endif
+#endif
/* Does the __typeof__ keyword work? This could be done by
