diff --git a/configure b/configure
index 183914e022..b4490d2518 100755
--- a/configure
+++ b/configure
@@ -6653,14 +6653,14 @@ EOF
 esac
 
 if test "x$GCC" = xyes; then
-  CFLAGS="${CFLAGS} -Wall"
+  CFLAGS="${CFLAGS} -Wall -Wno-unused -Wno-uninitialized -D_REENTRANT -DLEX_SCANNER"
 fi
 
 if test "x$GXX" = xyes; then
   if test "$wxUSE_MOTIF" = 1; then
-    CXXFLAGS="${CXXFLAGS} -Wall -Wno-unused"
+    CXXFLAGS="${CXXFLAGS} -Wall -Wno-unused -D_REENTRANT"
   else
-    CXXFLAGS="${CXXFLAGS} -Wall"
+    CXXFLAGS="${CXXFLAGS} -Wall -D_REENTRANT"
   fi
 fi
 
diff --git a/configure.in b/configure.in
index d1b8bf3462..419be3c0b6 100644
--- a/configure.in
+++ b/configure.in
@@ -1397,14 +1397,14 @@ case "${canonical}" in
 esac
 
 if test "x$GCC" = xyes; then
-  CFLAGS="${CFLAGS} -Wall"
+  CFLAGS="${CFLAGS} -Wall -Wno-unused -Wno-uninitialized -D_REENTRANT -DLEX_SCANNER"
 fi
 
 if test "x$GXX" = xyes; then
   if test "$wxUSE_MOTIF" = 1; then
-    CXXFLAGS="${CXXFLAGS} -Wall -Wno-unused"
+    CXXFLAGS="${CXXFLAGS} -Wall -Wno-unused -D_REENTRANT"
   else
-    CXXFLAGS="${CXXFLAGS} -Wall"
+    CXXFLAGS="${CXXFLAGS} -Wall -D_REENTRANT"
   fi
 fi