gnu.cfg: Added support for secure_getenv()

cfg/gnu.cfg

@@ -140,6 +140,19 @@
     <arg nr="variadic" direction="in">
       <not-uninit/>
     </arg>
+  </function>
+    <!-- https://man7.org/linux/man-pages/man3/getenv.3.html -->
+    <!-- char * secure_getenv(const char *name); -->
+  <function name="secure_getenv">
+    <use-retval/>
+    <returnValue type="char *"/>
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1" direction="in">
+      <not-null/>
+      <not-uninit/>
+      <strz/>
+    </arg>
   </function>
   <!-- https://gcc.gnu.org/onlinedocs/gcc-6.2.0/gcc/Alignment.html -->
   <!-- __alignof__ is used like sizeof -->