Implemented strcat() and strchr()

photon/libc/include/string.h

@@ -12,6 +12,8 @@ extern int memcmp(const void *a, const void *b, size_t sz);
 extern void *memmove(void *dest, const void *src, size_t sz);
 extern void *memset(void *ptr, int value, size_t sz);
 
+extern char *strcat(char *dest, const char *src);
+
 extern size_t strlen(const char *str);
 extern int strcmp(const char *a, const char *b);
 extern int strncmp(const char *a, const char *b, size_t sz);
@@ -19,6 +21,7 @@ extern int strncmp(const char *a, const char *b, size_t sz);
 extern char *strcpy(char *dest, const char *src);
 extern char *strncpy(char *dest, const char *src, size_t sz);
 
+extern char *strchr(const char *str, int ch);
 extern char *strrchr(const char *s, int c);
 extern size_t strcspn(const char *str1, const char *str2);
 

photon/libc/string/strcat.c

@@ -0,0 +1,8 @@
+#include <string.h>
+
+char *strcat(char *dest, const char *src)
+{
+    size_t len = strlen(dest);
+    strcpy(dest + len, src);
+    return dest;
+}

photon/libc/string/strchr.c

@@ -0,0 +1,14 @@
+#include <string.h>
+
+char *strchr(const char *str, int ch)
+{
+    char c = ch;
+
+    for (size_t i = 0; str[i]; i++) {
+        if (str[i] == c) {
+            return (char *)&str[i];
+        }
+    }
+
+    return NULL;
+}