From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sun, 20 Dec 2020 13:55:40 -0800
Subject: [PATCH 2/2] Pass -mshstk to the compiler when Intel CET is enable

Copied from PCRE2.
---
 CMakeLists.txt | 18 ++++++++++++++++++
 Makefile.am    |  3 +++
 configure.ac   | 15 +++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 858a34b..74c27e9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,6 +112,24 @@ CHECK_FUNCTION_EXISTS(_strtoi64 HAVE__STRTOI64)
 CHECK_TYPE_SIZE("long long"             LONG_LONG)
 CHECK_TYPE_SIZE("unsigned long long"    UNSIGNED_LONG_LONG)
 
+# Check whether Intel CET is enabled, and if so, adjust compiler flags. This
+# code was written by PH, trying to imitate the logic from the autotools
+# configuration.
+
+CHECK_C_SOURCE_COMPILES(
+  "#ifndef __CET__
+   #error CET is not enabled
+   #endif
+   int main() { return 0; }"
+  INTEL_CET_ENABLED
+)
+
+IF (INTEL_CET_ENABLED)
+  SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mshstk")
+ENDIF(INTEL_CET_ENABLED)
+
+
+
 # User-configurable options
 #
 # (Note: CMakeSetup displays these in alphabetical order, regardless of
diff --git a/Makefile.am b/Makefile.am
index 22b6947..984c686 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -250,6 +250,7 @@ libpcre_la_SOURCES = \
 
 libpcre_la_CFLAGS = \
   $(VISIBILITY_CFLAGS) \
+  $(CET_CFLAGS) \
   $(AM_CFLAGS)
 
 libpcre_la_LIBADD =
@@ -289,6 +290,7 @@ libpcre16_la_SOURCES = \
 
 libpcre16_la_CFLAGS = \
   $(VISIBILITY_CFLAGS) \
+  $(CET_CFLAGS) \
   $(AM_CFLAGS)
 
 libpcre16_la_LIBADD =
@@ -328,6 +330,7 @@ libpcre32_la_SOURCES = \
 
 libpcre32_la_CFLAGS = \
   $(VISIBILITY_CFLAGS) \
+  $(CET_CFLAGS) \
   $(AM_CFLAGS)
 
 libpcre32_la_LIBADD =
diff --git a/configure.ac b/configure.ac
index 6a3e5f3..15f37d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1043,6 +1043,21 @@ fi # enable_coverage
 
 AM_CONDITIONAL([WITH_GCOV],[test "x$enable_coverage" = "xyes"])
 
+AC_MSG_CHECKING([whether Intel CET is enabled])
+AC_LANG_PUSH([C])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,
+                   [[#ifndef __CET__
+# error CET is not enabled
+#endif]])],
+                   [intel_cet_enabled=yes],
+                   [intel_cet_enabled=no])
+AC_MSG_RESULT([$intel_cet_enabled])
+if test "$intel_cet_enabled" = yes; then
+  CET_CFLAGS="-mshstk"
+  AC_SUBST([CET_CFLAGS])
+fi
+AC_LANG_POP([C])
+
 # Produce these files, in addition to config.h.
 AC_CONFIG_FILES(
 	Makefile
-- 
2.34.1