Various additions and fixes.
diff --git a/src/lib9/cistrstr.c b/src/lib9/cistrstr.c
new file mode 100644
index 0000000..0a11322
--- /dev/null
+++ b/src/lib9/cistrstr.c
@@ -0,0 +1,23 @@
+#include <u.h>
+#include <libc.h>
+
+char*
+cistrstr(char *s, char *sub)
+{
+ int c, csub, n;
+
+ csub = *sub;
+ if(csub == '\0')
+ return s;
+ if(csub >= 'A' && csub <= 'Z')
+ csub -= 'A' - 'a';
+ sub++;
+ n = strlen(sub);
+ for(; c = *s; s++){
+ if(c >= 'A' && c <= 'Z')
+ c -= 'A' - 'a';
+ if(c == csub && cistrncmp(s+1, sub, n) == 0)
+ return s;
+ }
+ return nil;
+}
