[liba] Add strchr to string.h

Change-Id: I6651daa030ad6dc5e567bb78f2f22d48f07524aa

liba/Makefile

@@ -16,6 +16,7 @@ objs += $(addprefix liba/src/, \
   memmove.o \
   memset.o \
   strcmp.o \
+  strchr.o \
   strlcpy.o \
   strlen.o \
   external/sqlite/mem5.o \

liba/include/string.h

@@ -10,9 +10,11 @@ int memcmp(const void * s1, const void * s2, size_t n);
 void * memcpy(void * dst, const void * src, size_t n);
 void * memmove(void * dst, const void * src, size_t n);
 void * memset(void * b, int c, size_t len);
-size_t strlen(const char * s);
-int strcmp(const char *s1, const char *s2);
+
+char * strchr(const char * s, int c);
+int strcmp(const char * s1, const char * s2);
 size_t strlcpy(char * dst, const char * src, size_t len);
+size_t strlen(const char * s);
 
 LIBA_END_DECLS
 

liba/src/strchr.c

@@ -0,0 +1,11 @@
+#include <string.h>
+
+char * strchr(const char * s, int c) {
+  while (*s != NULL && *s != c) {
+    s++;
+  }
+  if (*s == c) {
+    return (char *)s;
+  }
+  return NULL;
+}