diff --git a/expat/Changes b/expat/Changes
index e3b6c5a6..a673f2fd 100644
--- a/expat/Changes
+++ b/expat/Changes
@@ -19,7 +19,11 @@ Release 2.??? ????????????????
                     quality entropy enabled, e.g. with CMake; commit
                     ff0207e6076e9828e536b8d9cd45c9c92069b895
 
+        Bug fixes:
+             #69  Fix improper use of unsigned long long integer literals
+
         Other changes:
+             #73  Start requiring a C99 compiler
              #49  Fix "==" Bashism in configure script
              #50  Fix too eager getrandom detection for Debian GNU/kFreeBSD
              #52    and macOS
@@ -32,6 +36,7 @@ Release 2.??? ????????????????
              #72  CMake: Resolve mistaken executable permissions
 
         Special thanks to:
+            Alexander Bluhm
             Ben Boeckel
             Cătălin Răceanu
             Kerin Millar
diff --git a/expat/configure.ac b/expat/configure.ac
index 444c0026..876a09ee 100644
--- a/expat/configure.ac
+++ b/expat/configure.ac
@@ -61,7 +61,7 @@ AC_SUBST(LIBREVISION)
 AC_SUBST(LIBAGE)
 
 dnl Checks for programs.
-AC_PROG_CC
+AC_PROG_CC_C99
 AC_PROG_CXX
 AC_PROG_INSTALL
 
@@ -174,37 +174,6 @@ else
 fi
 AC_SUBST(FILEMAP)
 
-dnl Needed for the test support code; this was found at
-dnl http://lists.gnu.org/archive/html/bug-autoconf/2002-07/msg00028.html
-
-# AC_CPP_FUNC
-# ------------------ #
-# Checks to see if ANSI C99 CPP variable __func__ works.
-# If not, perhaps __FUNCTION__ works instead. 
-# If not, we'll just define __func__ to "". 
-AC_DEFUN([AC_CPP_FUNC],
-[AC_REQUIRE([AC_PROG_CC_STDC])dnl
-AC_CACHE_CHECK([for an ANSI C99-conforming __func__], ac_cv_cpp_func,
-[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
-[[const char *foo = __func__;]])],
-  [ac_cv_cpp_func=yes], 
-  [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
-[[const char *foo = __FUNCTION__;]])],
-  [ac_cv_cpp_func=__FUNCTION__], 
-  [ac_cv_cpp_func=no])])])
-if test $ac_cv_cpp_func = __FUNCTION__; then
-  AC_DEFINE(__func__,__FUNCTION__,
-            [Define to __FUNCTION__ or "" if `__func__' does not conform to 
-ANSI C.])
-elif test $ac_cv_cpp_func = no; then
-  AC_DEFINE(__func__,"",
-            [Define to __FUNCTION__ or "" if `__func__' does not conform to 
-ANSI C.])
-fi
-])# AC_CPP_FUNC
-
-AC_CPP_FUNC
-
 
 dnl Some basic configuration:
 AC_DEFINE([XML_NS], 1,
diff --git a/expat/coverage.sh b/expat/coverage.sh
index 4e4ff1e5..0600847a 100755
--- a/expat/coverage.sh
+++ b/expat/coverage.sh
@@ -95,7 +95,7 @@ _run() {
     local BASE_FLAGS='-pipe -Wall -Wextra -pedantic -Wno-overlength-strings'
     BASE_FLAGS+=' --coverage --no-inline'
 
-    local CFLAGS="-std=c89 ${BASE_FLAGS}"
+    local CFLAGS="-std=c99 ${BASE_FLAGS}"
     local CXXFLAGS="-std=c++98 ${BASE_FLAGS}"
 
     (
diff --git a/expat/lib/expat.h b/expat/lib/expat.h
index 28b0f954..efb7514a 100644
--- a/expat/lib/expat.h
+++ b/expat/lib/expat.h
@@ -24,7 +24,6 @@ extern "C" {
 struct XML_ParserStruct;
 typedef struct XML_ParserStruct *XML_Parser;
 
-/* Should this be defined using stdbool.h when C99 is available? */
 typedef unsigned char XML_Bool;
 #define XML_TRUE   ((XML_Bool) 1)
 #define XML_FALSE  ((XML_Bool) 0)
diff --git a/expat/lib/siphash.h b/expat/lib/siphash.h
index 753b7935..30a6f11d 100644
--- a/expat/lib/siphash.h
+++ b/expat/lib/siphash.h
@@ -12,6 +12,7 @@
  * HISTORY:
  *
  * 2017-07-05  (Sebastian Pipping)
+ *   - Use _SIP_ULL macro to not require a C++11 compiler if compiled as C++
  *   - Add const qualifiers at two places
  *   - Ensure <=80 characters line length (assuming tab width 4)
  *
@@ -22,7 +23,6 @@
  *   - Clarify license note in the header
  *   - Address C89 issues:
  *     - Stop using inline keyword (and let compiler decide)
- *     - Turn integer suffix ULL to UL
  *     - Replace _Bool by int
  *     - Turn macro siphash24 into a function
  *     - Address invalid conversion (void pointer) by explicit cast
@@ -94,6 +94,14 @@
 #endif
 
 
+/*
+ * Workaround to not require a C++11 compiler for using ULL suffix
+ * if this code is included and compiled as C++; related GCC warning is:
+ * warning: use of C++11 long long integer constant [-Wlong-long]
+ */
+#define _SIP_ULL(high, low)  (((uint64_t)high << 32) | low)
+
+
 #define SIP_ROTL(x, b) (uint64_t)(((x) << (b)) | ( (x) >> (64 - (b))))
 
 #define SIP_U32TO8_LE(p, v) \
@@ -175,10 +183,10 @@ static void sip_round(struct siphash *H, const int rounds) {
 
 static struct siphash *sip24_init(struct siphash *H,
 		const struct sipkey *key) {
-	H->v0 = 0x736f6d6570736575UL ^ key->k[0];
-	H->v1 = 0x646f72616e646f6dUL ^ key->k[1];
-	H->v2 = 0x6c7967656e657261UL ^ key->k[0];
-	H->v3 = 0x7465646279746573UL ^ key->k[1];
+	H->v0 = _SIP_ULL(0x736f6d65U, 0x70736575U) ^ key->k[0];
+	H->v1 = _SIP_ULL(0x646f7261U, 0x6e646f6dU) ^ key->k[1];
+	H->v2 = _SIP_ULL(0x6c796765U, 0x6e657261U) ^ key->k[0];
+	H->v3 = _SIP_ULL(0x74656462U, 0x79746573U) ^ key->k[1];
 
 	H->p = H->buf;
 	H->c = 0;
diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index a540af1d..970e12b5 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -864,7 +864,7 @@ generate_hash_secret_salt(XML_Parser parser)
     return ENTROPY_DEBUG("fallback(4)", entropy * 2147483647);
   } else {
     return ENTROPY_DEBUG("fallback(8)",
-        entropy * (unsigned long)2305843009213693951);
+        entropy * (unsigned long)2305843009213693951ULL);
   }
 #endif
 }
diff --git a/expat/qa.sh b/expat/qa.sh
index 56bc3492..5f7ffdee 100755
--- a/expat/qa.sh
+++ b/expat/qa.sh
@@ -76,7 +76,7 @@ main() {
         ;;
     esac
 
-    local CFLAGS="-std=c89 ${BASE_FLAGS} ${CFLAGS:-}"
+    local CFLAGS="-std=c99 ${BASE_FLAGS} ${CFLAGS:-}"
     local CXXFLAGS="-std=c++98 ${BASE_FLAGS} ${CXXFLAGS:-}"
 
     (
diff --git a/expat/tests/minicheck.h b/expat/tests/minicheck.h
index 319c981d..3702cf81 100644
--- a/expat/tests/minicheck.h
+++ b/expat/tests/minicheck.h
@@ -26,12 +26,6 @@ extern "C" {
 #define __func__ __FUNCTION__
 #endif
 
-/* ISO C90 does not support '__func__' predefined identifier */
-#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ < 199901)) || \
-    (defined(__GNUC__) && !defined(__STDC_VERSION__))
-# define __func__ "(unknown)"
-#endif
-
 #define START_TEST(testname) static void testname(void) { \
     _check_set_test_info(__func__, __FILE__, __LINE__);   \
     {
diff --git a/expat/tests/runtests.c b/expat/tests/runtests.c
index 3b71aa90..5a4b49f7 100644
--- a/expat/tests/runtests.c
+++ b/expat/tests/runtests.c
@@ -247,7 +247,7 @@ START_TEST(test_siphash_spec)
     const char message[] = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09"
             "\x0a\x0b\x0c\x0d\x0e";
     const size_t len = sizeof(message) - 1;
-    const uint64_t expected = 0xa129ca6149be45e5U;
+    const uint64_t expected = _SIP_ULL(0xa129ca61U, 0x49be45e5U);
     struct siphash state;
     struct sipkey key;
     (void)sip_tobin;