diff --git a/src/auto/configure b/src/auto/configure
index b4745ea..34770f8 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -4114,9 +4114,9 @@
   fi
 fi
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for recent clang version" >&5
-$as_echo_n "checking for recent clang version... " >&6; }
-CLANG_VERSION_STRING=`$CC --version 2>/dev/null | sed  -n -e 's/^.*clang.*\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\).*$/\1/p'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for clang version" >&5
+$as_echo_n "checking for clang version... " >&6; }
+CLANG_VERSION_STRING=`$CC --version 2>/dev/null | sed  -n -e 's/^.*clang[^0-9]*\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\).*$/\1/p'`
 if test x"$CLANG_VERSION_STRING" != x"" ; then
   CLANG_MAJOR=`echo "$CLANG_VERSION_STRING" | sed -n -e 's/\([0-9][0-9]*\)\.[0-9][0-9]*\.[0-9][0-9]*/\1/p'`
   CLANG_MINOR=`echo "$CLANG_VERSION_STRING" | sed -n -e 's/[0-9][0-9]*\.\([0-9][0-9]*\)\.[0-9][0-9]*/\1/p'`
@@ -4124,12 +4124,19 @@
   CLANG_VERSION=`expr $CLANG_MAJOR '*' 1000000 '+' $CLANG_MINOR '*' 1000 '+' $CLANG_REVISION`
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CLANG_VERSION" >&5
 $as_echo "$CLANG_VERSION" >&6; }
-          if test "$CLANG_VERSION" -ge 500002075 ; then
-    CFLAGS=`echo "$CFLAGS" | sed -n -e 's/-fno-strength-reduce/ /p'`
+          { $as_echo "$as_me:${as_lineno-$LINENO}: checking if clang supports -fno-strength-reduce" >&5
+$as_echo_n "checking if clang supports -fno-strength-reduce... " >&6; }
+  if test "$CLANG_VERSION" -ge 500002075 ; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+    CFLAGS=`echo "$CFLAGS" | sed -e 's/-fno-strength-reduce/ /'`
+  else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
   fi
 else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: N/A" >&5
+$as_echo "N/A" >&6; }
 fi
 
 CROSS_COMPILING=
@@ -10094,6 +10101,18 @@
 
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for /proc/self/exe" >&5
+$as_echo_n "checking for /proc/self/exe... " >&6; }
+if test -L "/proc/self/exe"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+    $as_echo "#define HAVE_PROC_SELF_EXE 1" >>confdefs.h
+
+else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for CYGWIN or MSYS environment" >&5
 $as_echo_n "checking for CYGWIN or MSYS environment... " >&6; }
 case `uname` in