cgen: use a guarded include for <inttypes.h> too

vlib/v/gen/cgen.v

@@ -282,7 +282,7 @@ pub fn (mut g Gen) init() {
 		g.cheaders.writeln(g.pref.custom_prelude)
 	} else if !g.pref.no_preludes {
 		g.cheaders.writeln('// Generated by the V compiler')
-		g.cheaders.writeln('#include <inttypes.h>') // int64_t etc
+		g.cheaders.writeln(get_guarded_include_text('<inttypes.h>', 'Please install build-essentials')) // int64_t etc
 		g.cheaders.writeln(c_builtin_types)
 		if g.pref.is_bare {
 			g.cheaders.writeln(bare_c_headers)
@@ -979,19 +979,7 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 				} else {
 					missing_message += ' Please install the corresponding development headers.'
 				}
-				mut guarded_include := '
-				|#if defined(__has_include)
-				|
-				|#if __has_include($node.main)
-				|#include $node.main
-				|#else
-				|#error VERROR_MESSAGE $missing_message
-				|#endif
-				|
-				|#else
-				|#include $node.main
-				|#endif
-				'.strip_margin()
+				mut guarded_include := get_guarded_include_text(node.main, missing_message)
 				if node.main == '<errno.h>' {
 					// fails with musl-gcc and msvc; but an unguarded include works:
 					guarded_include = '#include $node.main'
@@ -5533,3 +5521,20 @@ fn (mut g Gen) panic_debug_info(pos token.Position) (int, string, string, string
 	pamod := g.fn_decl.modname()
 	return paline, pafile, pamod, pafn
 }
+
+pub fn get_guarded_include_text(iname string, imessage string) string {
+	res := '
+	|#if defined(__has_include)
+	|
+	|#if __has_include($iname)
+	|#include $iname
+	|#else
+	|#error VERROR_MESSAGE $imessage
+	|#endif
+	|
+	|#else
+	|#include $iname
+	|#endif
+	'.strip_margin()
+	return res                
+}