misc: Address compiler warning on unused variables

abis_nm.c: In function ‘abis_nm_get_attr’:
abis_nm.c:1380:11: warning: unused variable ‘cur’ [-Wunused-variable]

abis_nm.c: In function ‘ipac_parse_bcch_info’:
abis_nm.c:2588:11: warning: variable ‘len’ set but not used [-Wunused-but-set-variable]

bts_nokia_site.c:1310:6: warning: variable ‘constructed’ set but not used [-Wunused-but-set-variable]
bts_nokia_site.c: At top level:
bts_nokia_site.c:1364:12: warning: ‘dump_elements’ defined but not used [-Wunused-function]

gsm_04_08.c: In function ‘mm_rx_loc_upd_req’:
gsm_04_08.c:521:6: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]

osmo_msc.c: In function ‘msc_ciph_m_compl’:
osmo_msc.c:122:7: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]

bts_hsl_femtocell.c: In function ‘hslfemto_bootstrap_om’:
bts_hsl_femtocell.c:101:11: warning: variable ‘cur’ set but not used [-Wunused-but-set-variable]

bts_hsl_femtocell.c: In function ‘hsl_drop_oml’:
bts_hsl_femtocell.c:232:21: warning: variable ‘line’ set but not used [-Wunused-but-set-variable]

handover_logic.c: In function ‘ho_chan_activ_ack’:
handover_logic.c:197:6: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]
diff --git a/openbsc/src/libbsc/abis_nm.c b/openbsc/src/libbsc/abis_nm.c
index ee0dd60..23d5fa3 100644
--- a/openbsc/src/libbsc/abis_nm.c
+++ b/openbsc/src/libbsc/abis_nm.c
@@ -1377,7 +1377,6 @@
 {
 	struct abis_om_hdr *oh;
 	struct msgb *msg = nm_msgb_alloc();
-	uint8_t *cur;
 
 	DEBUGP(DNM, "Get Attr (bts=%d)\n", bts->nr);
 
@@ -2586,7 +2585,7 @@
 int ipac_parse_bcch_info(struct ipac_bcch_info *binf, uint8_t *buf)
 {
 	uint8_t *cur = buf;
-	uint16_t len;
+	uint16_t len __attribute__((unused));
 
 	memset(binf, 0, sizeof(*binf));