lc15bts.h: add missing extern keyword

Fix linker errors with ld from binutils 2.35.2 in Debian 11:

/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x100): multiple definition of `lc15bts_l1prim_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x80): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x2a0): multiple definition of `lc15bts_sysprim_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x220): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x420): multiple definition of `lc15bts_l1sapi_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x3a0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x5a0): multiple definition of `lc15bts_l1status_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x520): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x760): multiple definition of `lc15bts_tracef_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x6e0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0x940): multiple definition of `lc15bts_tracef_docs'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x8c0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0xb20): multiple definition of `lc15bts_tch_pl_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xaa0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0xc20): multiple definition of `lc15bts_clksrc_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xba0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0xcc0): multiple definition of `lc15bts_dir_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xc40): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15_l1_hw.o:(.rodata+0xd20): multiple definition of `pdch_msu_size'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xca0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x0): multiple definition of `lc15bts_l1prim_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x80): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x1a0): multiple definition of `lc15bts_sysprim_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x220): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x320): multiple definition of `lc15bts_l1sapi_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x3a0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x4a0): multiple definition of `lc15bts_l1status_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x520): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x660): multiple definition of `lc15bts_tracef_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x6e0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0x840): multiple definition of `lc15bts_tracef_docs'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0x8c0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0xa20): multiple definition of `lc15bts_tch_pl_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xaa0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.rodata+0x820): multiple definition of `lc15bts_clksrc_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xba0): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.data.rel.ro.local+0xb20): multiple definition of `lc15bts_dir_names'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xc40): first defined here
/usr/bin/ld: osmo-bts-litecell15/lc15bts.o:(.rodata+0x8e0): multiple definition of `pdch_msu_size'; osmo-bts-litecell15/lc15_l1_if.o:(.rodata+0xca0): first defined here

Change-Id: I33c061e79536a6e9ea7289a245af996e8d17c6ce
diff --git a/src/osmo-bts-litecell15/lc15bts.h b/src/osmo-bts-litecell15/lc15bts.h
index 4c40db0..31ca923 100644
--- a/src/osmo-bts-litecell15/lc15bts.h
+++ b/src/osmo-bts-litecell15/lc15bts.h
@@ -23,24 +23,24 @@
 };
 
 enum l1prim_type lc15bts_get_l1prim_type(GsmL1_PrimId_t id);
-const struct value_string lc15bts_l1prim_names[GsmL1_PrimId_NUM+1];
+extern const struct value_string lc15bts_l1prim_names[GsmL1_PrimId_NUM+1];
 GsmL1_PrimId_t lc15bts_get_l1prim_conf(GsmL1_PrimId_t id);
 
 enum l1prim_type lc15bts_get_sysprim_type(Litecell15_PrimId_t id);
-const struct value_string lc15bts_sysprim_names[Litecell15_PrimId_NUM+1];
+extern const struct value_string lc15bts_sysprim_names[Litecell15_PrimId_NUM+1];
 Litecell15_PrimId_t lc15bts_get_sysprim_conf(Litecell15_PrimId_t id);
 
-const struct value_string lc15bts_l1sapi_names[GsmL1_Sapi_NUM+1];
-const struct value_string lc15bts_l1status_names[GSML1_STATUS_NUM+1];
+extern const struct value_string lc15bts_l1sapi_names[GsmL1_Sapi_NUM+1];
+extern const struct value_string lc15bts_l1status_names[GSML1_STATUS_NUM+1];
 
-const struct value_string lc15bts_tracef_names[29];
-const struct value_string lc15bts_tracef_docs[29];
+extern const struct value_string lc15bts_tracef_names[29];
+extern const struct value_string lc15bts_tracef_docs[29];
 
-const struct value_string lc15bts_tch_pl_names[15];
+extern const struct value_string lc15bts_tch_pl_names[15];
 
-const struct value_string lc15bts_clksrc_names[10];
+extern const struct value_string lc15bts_clksrc_names[10];
 
-const struct value_string lc15bts_dir_names[6];
+extern const struct value_string lc15bts_dir_names[6];
 
 enum pdch_cs {
 	PDCH_CS_1,
@@ -59,6 +59,6 @@
 	_NUM_PDCH_CS
 };
 
-const uint8_t pdch_msu_size[_NUM_PDCH_CS];
+extern const uint8_t pdch_msu_size[_NUM_PDCH_CS];
 
 #endif /* LC15BTS_H */