Workaround Solaris autoconf interaction to look for C99.

The ICC check seems to abort prematurely, so doing the test from
within the function doesn't work.  Instead, get the vars set, and do
the check based on the var values.

configure.ac

@@ -20,23 +20,20 @@ AC_DEFUN([DETECT_ICC],
     if test "$GCC" = "yes"; then
        dnl check if this is icc acting as gcc in disguise
        AC_EGREP_CPP([^__INTEL_COMPILER], [__INTEL_COMPILER],
-         dnl action if the text is found, this it has not been replaced by the
-         dnl cpp
-         ICC="no"
-         [$2],
-         dnl the text was not found, it was replaced by the cpp
-         ICC="yes"
+         AC_MSG_RESULT([no])
+         [$2]
+         ICC="no",
          AC_MSG_RESULT([yes])
          [$1]
-       )
-    fi
-    if test "$ICC" = "no"; then
-        # this is not ICC
-        AC_MSG_RESULT([no])
+         ICC="yes")
     fi
 ])
 
-DETECT_ICC([], [AC_PROG_CC_C99])
+DETECT_ICC([], [])
+
+if test "$ICC" == "no"; then
+   AC_PROG_CC_C99
+fi
 
 AM_PROG_CC_C_O
 AC_PROG_INSTALL