build-baremetal: enable parallel build and target selection just like build-userland

The factoring out also led to some small bugs being found and solved ;-)

baremetal/arch/aarch64/multicore.S

@@ -36,7 +36,7 @@ cpu1_sleep_forever:
 cpu0_only:
     /* Only CPU 0 reaches this point. */
 
-#if !defined(GEM5)
+#if !LKMC_GEM5
     /* Wake up CPU 1 from initial sleep!
      * See:https://github.com/cirosantilli/linux-kernel-module-cheat#psci
      */

baremetal/arch/aarch64/svc.c

@@ -1,5 +1,6 @@
 /* https://github.com/cirosantilli/linux-kernel-module-cheat#svc */
 
+#include <assert.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -57,8 +58,8 @@ int main(void) {
     printf("daif 0x%" PRIx32 "\n", lkmc_sysreg_daif_read());
     printf("spsel 0x%" PRIx32 "\n", lkmc_sysreg_spsel_read());
     printf("vbar_el1 0x%" PRIx64 "\n", lkmc_sysreg_vbar_el1_read());
-    lkmc_assert(myvar == 0);
+    assert(myvar == 0);
     LKMC_SVC(0x42);
-    lkmc_assert(myvar == 1);
+    assert(myvar == 1);
     return 0;
 }

baremetal/arch/arm/dump_regs.c

@@ -5,7 +5,7 @@
 
 int main(void) {
     uint32_t cpsr;
-    uint32_t mvfr1;
+    /*uint32_t mvfr1;*/
     __asm__ ("mrs %0, cpsr" : "=r" (cpsr) : :);
     /* TODO this is blowing up an exception, how to I read from it? */
     /*__asm__ ("vmrs %0, mvfr1" : "=r" (mvfr1) : :);*/

baremetal/arch/arm/multicore.S

@@ -19,7 +19,7 @@ cpu1_sleep_forever:
     wfe
     b cpu1_sleep_forever
 cpu0_only:
-#if !defined(GEM5)
+#if !LKMC_GEM5
     /* PSCI CPU_ON. */
     ldr r0, =0x84000003
     mov r1, #1