posix.cfg: Added support for wcwidth().

cfg/posix.cfg

@@ -4729,6 +4729,18 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <valid>0:</valid>
     </arg>
   </function>
+  <!-- https://man7.org/linux/man-pages/man3/wcwidth.3.html -->
+  <!-- int wcwidth(wchar_t c); -->
+  <function name="wcwidth">
+    <returnValue type="int"/>
+    <use-retval/>
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+      <not-bool/>
+    </arg>
+  </function>
   <!-- http://man7.org/linux/man-pages/man3/ffs.3.html -->
   <!-- int ffs(int i); -->
   <function name="ffs">

test/cfg/posix.c

@@ -31,6 +31,15 @@
 #include <wchar.h>
 #include <string.h>
 
+int uninitvar_wcwidth(const wchar_t c)
+{
+    wchar_t wc;
+    // cppcheck-suppress uninitvar
+    (void)wcwidth(wc);
+    // No warning is expected
+    return wcwidth(c);
+}
+
 int nullPointer_wcsnlen(const wchar_t *s, size_t n)
 {
     // cppcheck-suppress nullPointer