diff --git a/acinclude.m4 b/acinclude.m4
index abc48ada5..60a41f311 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -475,3 +475,89 @@ if test "$ac_cv_func_gethostbyname_r" = "yes"; then
   fi
 fi
 ])
+
+dnl We create a function for detecting which compiler we use and then set as
+dnl pendantic compiler options as possible for that particular compiler. The
+dnl options are only used for debug-builds.
+
+AC_DEFUN([CURL_CC_DEBUG_OPTS],
+[
+    if test "$GCC" = "yes"; then
+
+       dnl figure out gcc version!
+       AC_MSG_CHECKING([gcc version])
+       gccver=`$CC -dumpversion`
+       num1=`echo $gccver | cut -d . -f1`
+       num2=`echo $gccver | cut -d . -f2`
+       gccnum=`(expr $num1 "*" 100 + $num2) 2>/dev/null`
+       AC_MSG_RESULT($gccver)
+
+       AC_MSG_CHECKING([if this is icc in disguise])
+       AC_EGREP_CPP([^__ICC], [__ICC],
+         dnl action if the text is found, this it has not been replaced by the
+         dnl cpp
+         [ICC="no"]
+         AC_MSG_RESULT([no]),
+         dnl the text was not found, it was replaced by the cpp
+         [ICC="yes"]
+         AC_MSG_RESULT([yes])
+       )
+
+       if test "$ICC" = "yes"; then
+         dnl this is icc, not gcc.
+         WARN = ""
+       else dnl $ICC = yes
+         dnl 
+         WARN="-W -Wall -Wwrite-strings -pedantic -Wno-long-long -Wundef -Wpointer-arith -Wnested-externs -Winline -Wmissing-declarations -Wmissing-prototypes -Wsign-compare"
+
+         dnl -Wcast-align is a bit too annoying ;-)
+
+         if test "$gccnum" -ge "296"; then
+           dnl gcc 2.96 or later
+           WARN="$WARN -Wfloat-equal"
+
+           if test "$gccnum" -gt "296"; then
+             dnl this option does not exist in 2.96
+             WARN="$WARN -Wno-format-nonliteral"
+           fi
+
+           dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
+           dnl on i686-Linux as it gives us heaps with false positives
+           if test "$gccnum" -ge "303"; then
+             dnl gcc 3.3 and later
+             WARN="$WARN -Wendif-labels -Wstrict-prototypes"
+           fi
+         fi
+
+         NEWFLAGS=""
+         for flag in $CPPFLAGS; do
+           case "$flag" in
+            -I*)
+              dnl include path
+              add=`echo $flag | sed 's/^-I/-isystem /g'`
+              NEWFLAGS="$NEWFLAGS $add"
+              ;;
+           esac
+         done
+
+         CFLAGS="$CFLAGS $WARN $NEWFLAGS"
+       fi dnl $ICC = no
+
+    fi dnl $GCC = yes
+
+    dnl strip off optimizer flags
+    NEWFLAGS=""
+    for flag in $CFLAGS; do
+      case "$flag" in
+      -O*)
+        dnl echo "cut off $flag"
+        ;;
+      *)
+        NEWFLAGS="$NEWFLAGS $flag"
+        ;;
+      esac
+    done
+    CFLAGS=$NEWFLAGS
+
+]) dnl end of AC_DEFUN()
+
diff --git a/configure.ac b/configure.ac
index ce84cba55..a746aa5d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1188,72 +1188,14 @@ AC_HELP_STRING([--disable-debug],[Disable debug options]),
   *)   AC_MSG_RESULT(yes)
 
     CPPFLAGS="$CPPFLAGS -DCURLDEBUG"
-    CFLAGS="$CFLAGS -g" 
-    if test "$GCC" = "yes"; then
+    CFLAGS="$CFLAGS -g"
 
-       dnl figure out gcc version!
-       AC_MSG_CHECKING([gcc version])
-       gccver=`$CC -dumpversion`
-       num1=`echo $gccver | cut -d . -f1`
-       num2=`echo $gccver | cut -d . -f2`
-       gccnum=`(expr $num1 "*" 100 + $num2) 2>/dev/null`
-       AC_MSG_RESULT($gccver)
-
-       if test "$gccnum" -lt "500"; then
-         dnl we only like gcc less than 5.0, since if it is above that it is
-         dnl likely just a compiler that looks like gcc (like icc 8.0)!
-         dnl here's the standard setup
-         WARN="-W -Wall -Wwrite-strings -pedantic -Wno-long-long -Wundef -Wpointer-arith -Wnested-externs -Winline -Wmissing-declarations -Wmissing-prototypes -Wsign-compare"
-
-         dnl -Wcast-align is a bit too annoying ;-)
-
-         if test "$gccnum" -ge "296"; then
-           dnl gcc 2.96 or later
-           WARN="$WARN -Wfloat-equal"
-
-           if test "$gccnum" -gt "296"; then
-             dnl this option does not exist in 2.96
-             WARN="$WARN -Wno-format-nonliteral"
-           fi
-
-           dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
-           dnl on i686-Linux as it gives us heaps with false positives
-           if test "$gccnum" -ge "303"; then
-             dnl gcc 3.3 and later
-             WARN="$WARN -Wendif-labels -Wstrict-prototypes"
-           fi
-         fi
-
-         NEWFLAGS=""
-         for flag in $CPPFLAGS; do
-           case "$flag" in
-            -I*)
-              dnl include path
-              add=`echo $flag | sed 's/^-I/-isystem /g'`
-              NEWFLAGS="$NEWFLAGS $add"
-              ;;
-           esac
-         done
-
-         CFLAGS="$CFLAGS $WARN $NEWFLAGS"
-       fi
-
-    fi
-    dnl strip off optimizer flags
-    NEWFLAGS=""
-    for flag in $CFLAGS; do
-      case "$flag" in
-      -O*)
-        dnl echo "cut off $flag"
-        ;;
-      *)
-        NEWFLAGS="$NEWFLAGS $flag"
-        ;;
-      esac
-    done
-    CFLAGS=$NEWFLAGS
+    dnl set compiler "debug" options to become more picky, and remove
+    dnl optimize options from CFLAGS
+    CURL_CC_DEBUG_OPTS
        ;;
-  esac ],
+  esac
+ ],
        AC_MSG_RESULT(no)
 )