diff --git a/cfg/std.cfg b/cfg/std.cfg
index d199c514b..7a9fe6829 100644
--- a/cfg/std.cfg
+++ b/cfg/std.cfg
@@ -1,29 +1,29 @@
 <?xml version="1.0"?>
 <def>
   <function name="abort"><noreturn>true</noreturn></function>
-  <function name="abs"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/><not-bool/></arg></function>
-  <function name="acos"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="abs"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/><not-bool/></arg></function>
+  <function name="acos"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
   <function name="asctime">
 	  <noreturn>false</noreturn>
 	  <leak-ignore/>
 	  <arg nr="1"><not-uninit/></arg>
   </function>
-  <function name="asin"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="atan"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="atan2"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg><arg nr="2"><not-uninit/></arg></function>
-  <function name="atof"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="atoi"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="atol"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="atoll"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="asin"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="atan"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="atan2"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg><arg nr="2"><not-uninit/></arg></function>
+  <function name="atof"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="atoi"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="atol"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="atoll"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
   <function name="calloc"><noreturn>false</noreturn><arg nr="1"><not-uninit/></arg><arg nr="2"><not-uninit/></arg></function>
-  <function name="ceil"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="ceil"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
   <function name="clearerr">
 	  <noreturn>false</noreturn>
 	  <leak-ignore/>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
   </function>
-  <function name="cos"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="cosh"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="cos"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="cosh"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
   <function name="ctime">
 	  <noreturn>false</noreturn>
 	  <leak-ignore/>
@@ -31,14 +31,15 @@
   </function>
   <function name="difftime"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg><arg nr="2"><not-null/><not-uninit/></arg></function>
   <function name="div">
+	  <pure/>
 	  <noreturn>false</noreturn>
 	  <leak-ignore/>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
 	  <arg nr="2"><not-null/><not-uninit/></arg>
   </function>
   <function name="exit"><noreturn>true</noreturn><arg nr="1"><not-uninit/></arg></function>
-  <function name="exp"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
-  <function name="fabs"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="exp"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
+  <function name="fabs"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-uninit/></arg></function>
   <function name="fclose">
 	  <noreturn>false</noreturn>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
@@ -73,8 +74,8 @@
 	  <arg nr="1"><not-null/><not-uninit/></arg>
 	  <arg nr="2"><not-null/><not-uninit/></arg>
   </function>
-  <function name="floor"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg></function>
-  <function name="fmod"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg><arg nr="2"><not-null/><not-uninit/></arg></function>
+  <function name="floor"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg></function>
+  <function name="fmod"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg><arg nr="2"><not-null/><not-uninit/></arg></function>
   <function name="fopen">
 	  <noreturn>false</noreturn>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
@@ -234,20 +235,21 @@
 	  <leak-ignore/>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
   </function>
-  <function name="isalnum"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isalpha"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isblank"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="iscntrl"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isdigit"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isgraph"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="islower"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isprint"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="ispunct"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isspace"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isupper"> <noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="isxdigit"> <noreturn>false</noreturn> <leak-ignore/> <arg nr="1"><valid>0:255</valid></arg> </function>
-  <function name="labs"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg></function>
+  <function name="isalnum"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isalpha"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isblank"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="iscntrl"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isdigit"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isgraph"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="islower"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isprint"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="ispunct"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isspace"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isupper"> <pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="isxdigit"><pure/><noreturn>false</noreturn> <leak-ignore/>  <arg nr="1"><valid>0:255</valid></arg> </function>
+  <function name="labs">    <pure/><noreturn>false</noreturn><leak-ignore/>   <arg nr="1"><not-null/><not-uninit/></arg></function>
   <function name="ldexp">
+       <pure/>
        <noreturn>false</noreturn>
        <leak-ignore/>
        <arg nr="1"><not-null/><not-uninit/></arg>
@@ -262,6 +264,7 @@
        <leak-ignore/>
   </function>
   <function name="ldiv">
+       <pure/>
        <noreturn>false</noreturn>
        <leak-ignore/>
        <arg nr="1"><not-null/><not-uninit/></arg>
@@ -283,6 +286,7 @@
   <function name="malloc"><noreturn>false</noreturn><arg nr="1"><not-uninit/></arg></function>
   <function name="alloca"><noreturn>false</noreturn><arg nr="1"><not-uninit/></arg></function>
   <function name="memchr">
+        <pure/>
         <noreturn>false</noreturn>
         <leak-ignore/>
         <arg nr="1"><not-null/><not-uninit/><minsize type="argvalue" arg="3"/></arg>
@@ -290,6 +294,7 @@
         <arg nr="3"><not-bool/><valid>0:</valid></arg>
   </function>
   <function name="memcmp">
+        <pure/>
         <noreturn>false</noreturn>
         <leak-ignore/>
         <arg nr="1"><not-null/><not-uninit/><minsize type="argvalue" arg="3"/></arg>
@@ -297,10 +302,10 @@
         <arg nr="3"><not-bool/><valid>0:</valid></arg>
   </function>
   <function name="memcpy">
-        <noreturn>false</noreturn>
-        <leak-ignore/>
-        <arg nr="1"><not-null/><minsize type="argvalue" arg="3"/></arg>
-	    <arg nr="2"><not-null/><not-uninit/><minsize type="argvalue" arg="3"/></arg>
+		<noreturn>false</noreturn>
+		<leak-ignore/>
+		<arg nr="1"><not-null/><minsize type="argvalue" arg="3"/></arg>
+		<arg nr="2"><not-null/><not-uninit/><minsize type="argvalue" arg="3"/></arg>
 		<arg nr="3"><not-bool/><valid>0:</valid></arg>
   </function>
   <function name="memmove">
@@ -334,6 +339,7 @@
 	  <arg nr="1"><not-uninit/></arg>
   </function>
   <function name="pow">
+       <pure/>
        <noreturn>false</noreturn>
        <leak-ignore/>
        <arg nr="1"><not-null/><not-uninit/></arg>
@@ -358,6 +364,7 @@
 	  <arg nr="any"><not-uninit/></arg>
   </function>
   <function name="bsearch">
+       <pure/>
        <noreturn>false</noreturn>
        <leak-ignore/>
        <arg nr="1"><not-null/><not-uninit/></arg>
@@ -416,7 +423,7 @@
 	  <leak-ignore/>
 	  <arg nr="1"><not-null/><not-uninit/></arg>
   </function>
-  <function name="round"><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg></function>
+  <function name="round"><pure/><noreturn>false</noreturn><leak-ignore/><arg nr="1"><not-null/><not-uninit/></arg></function>
   <function name="scanf">
 	  <noreturn>false</noreturn>
 	  <leak-ignore/>