1 files changed, 1 insertions, 1 deletions

diff --git a/scripts/basic/split-include.c b/scripts/basic/split-include.c
index a38ac3427..6ef29195e 100644
--- a/scripts/basic/split-include.c
+++ b/scripts/basic/split-include.c
@@ -116,7 +116,7 @@ int main(int argc, const char * argv [])
         /* We found #define CONFIG_foo or #undef CONFIG_foo.
          * Make the output file name. */
         str_config += sizeof(" CONFIG_") - 1;
-        for (itarget = 0; !isspace(str_config[itarget]); itarget++)
+        for (itarget = 0; !isspace((unsigned char)str_config[itarget]); itarget++)
         {
             int c = (unsigned char) str_config[itarget];
             if (isupper(c)) c = tolower(c);