target: move 'extern' decls to *.h files

The exception being declarations for drivers.  Those should
be split out in some clean way -- like driver add/remove calls
made by initialization code -- but that's for another day.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/armv7m.h

@@ -34,6 +34,12 @@
 #define ARMV7_GDB_HACKS
 #endif
 
+#ifdef ARMV7_GDB_HACKS
+extern uint8_t armv7m_gdb_dummy_cpsr_value[];
+extern struct reg armv7m_gdb_dummy_cpsr_reg;
+#endif
+
+
 enum armv7m_mode
 {
 	ARMV7M_MODE_THREAD = 0,