Look for ipopt by default

git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@17108 f25d12d1-65f4-0310-ae8a-bbce733d8d8e

configure.in

@@ -410,18 +410,20 @@ dnl should we use ipopt?
 
 AC_ARG_WITH(ipopt, [  --with-ipopt=DIR                 use ipopt for initialization], 
 [
+  WANT_IPOPT="$withval"
+], [
   WANT_IPOPT="yes"
+])
 
-  if test "$withval" = "yes"; then
-    AC_CHECK_HEADERS(coin/IpStdCInterface.h, [IPOPT_LDFLAGS="-lipopt -lcoinmumps"; IPOPT_CFLAGS=""], [NO_IPOPT="yes"])
-  else
-    IPOPT_DIR="$withval"
-    AC_CHECK_HEADERS($IPOPT_DIR/include/coin/IpStdCInterface.h, [AC_MSG_RESULT(ipopt directory: $IPOPT_DIR); IPOPT_LDFLAGS="-L'"$IPOPT_DIR"/lib' -lipopt -lcoinmumps"; IPOPT_CFLAGS="-I'"$IPOPT_DIR"/include'"], [NO_IPOPT="yes"])
-  fi
-], [
-  WANT_IPOPT="no"
+if test "$WANT_IPOPT" = "yes"; then
+  AC_CHECK_HEADERS(coin/IpStdCInterface.h, [IPOPT_LDFLAGS="-lipopt"; IPOPT_CFLAGS=""], [NO_IPOPT="yes"])
+elif test "$WANT_IPOPT" = "no"; then
   NO_IPOPT="yes"
-])
+else
+  IPOPT_DIR="$withval"
+  AC_CHECK_HEADERS($IPOPT_DIR/include/coin/IpStdCInterface.h, [AC_MSG_RESULT(ipopt directory: $IPOPT_DIR); IPOPT_LDFLAGS="-L'"$IPOPT_DIR"/lib' -lipopt"; IPOPT_CFLAGS="-I'"$IPOPT_DIR"/include'"], [NO_IPOPT="yes"])
+fi
+
 
 if ! test "$NO_IPOPT" = "yes"; then
   FINAL_MESSAGES="$FINAL_MESSAGES\nSimulations may use IPOPT: Yes"