res_ninit is available in glibc but not in uclibc or musl.

Signed-off-by: Alex Suykov <alex.suykov@gmail.com>

--- aiccu/common/resolver.c
+++ aiccu/common/resolver.c
@@ -26,7 +26,7 @@
 
 int getrrs(const char *label, int rrtype, void gotrec(unsigned int num, int type, const char *record))
 {
-#ifdef _LINUX
+#if defined(__GLIBC__) && !defined(__UCLIBC__)
 	struct __res_state	res;
 #endif
 	unsigned char		answer[8192];
@@ -38,7 +38,7 @@ int getrrs(const char *label, int rrtype
 	uint16_t		type = 0, class = 0;
 	uint32_t		ttl = 0;
 
-#ifdef _LINUX
+#if defined(__GLIBC__) && !defined(__UCLIBC__)
 	memset(&res, 0, sizeof(res));
 	res.options = RES_DEBUG;
 	res_ninit(&res);
@@ -47,7 +47,7 @@ int getrrs(const char *label, int rrtype
 #endif
 
 	memset(answer, 0, sizeof(answer));
-#ifdef _LINUX
+#if defined(__GLIBC__) && !defined(__UCLIBC__)
 	ret = res_nquery(&res, label, C_IN, rrtype, answer, sizeof(answer));
 #else
 	ret = res_query(label, C_IN, rrtype, answer, sizeof(answer));