diff --git a/VAX/tests/vax-diag_test.ini b/VAX/tests/vax-diag_test.ini
index 8180c7f3..b1fd0e4f 100644
--- a/VAX/tests/vax-diag_test.ini
+++ b/VAX/tests/vax-diag_test.ini
@@ -106,10 +106,11 @@ set env DIAG_TEST=%1
 set env DIAG_DESC=%2
 set env -a DIAG_ERRORS=1
 noexpect
+if (SIM_REGEX_TYPE == "") echof "Missing Regular Expression support - skipping %DIAG_TEST% test\n"; exit 0
 expect -r "Hard error" go -q
-expect -r "Pass \d+, test (\d+), subtest (\d+), error (\d+)," set env -a DIAG_ERRORS=_EXPECT_MATCH_GROUP_3; return
+expect -r "Pass 1, test ([0-9][0-9]*), subtest ([0-9][0-9]*), error ([0-9][0-9]*)," set env -a DIAG_ERRORS=_EXPECT_MATCH_GROUP_3; return
 expect -r "System fatal error while testing" go -q
-expect -r "\.\. End of run, (\d+) (error|errors) detected, pass count is \d+," set env -a DIAG_ERRORS=_EXPECT_MATCH_GROUP_1; go -q
+expect -r "\.\. End of run, ([0-9][0-9]*) (error|errors) detected, pass count is [0-9][0-9]*," set env -a DIAG_ERRORS=_EXPECT_MATCH_GROUP_1; go -q
 expect "DS> "
 if (DIAG_QUIET_MODE) echof "\nRunning - %DIAG_DESC% %DIAG_TEST%\n"
 send "RUN %DIAG_TEST%\r"
diff --git a/makefile b/makefile
index 7b739f95..49bee028 100644
--- a/makefile
+++ b/makefile
@@ -479,8 +479,8 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
       endif
     endif
   endif
-  # Find available RegEx library.  Prefer libpcreposix.
-  ifneq (,$(and $(call find_include,pcreposix),$(call find_include,pcre)))
+  # Find available RegEx library.  Prefer libpcreposix - except on OS X.
+  ifneq (,$(and $(call find_include,pcreposix),$(call find_include,pcre),$(subst Darwin,,$(OSTYPE))))
     ifneq (,$(and $(call find_lib,pcreposix),$(call find_lib,pcre)))
       OS_CCDEFS += -DHAVE_PCREPOSIX_H
       OS_LDFLAGS += -lpcreposix -lpcre