Add HASTIMERS probe to work around bug in gcc 9.3

lib/portability.c

@@ -678,4 +678,27 @@ int timer_settime(timer_t t, int flags, struct itimerspec *new, void *old)
   mangled.it_value.tv_usec = new->it_value.tv_nsec / 1000;
   return setitimer(ITIMER_REAL, &mangled, NULL);
 }
+// glibc requires -lrt for linux syscalls, which pulls in libgcc_eh.a for
+// static linking, and gcc 9.3 leaks pthread calls from that breaking the build
+// These are both just linux syscalls: wrap them ourselves
+#elif !CFG_TOYBOX_HASTIMERS
+int timer_create_wrap(clockid_t c, struct sigevent *se, timer_t *t)
+{
+  // convert overengineered structure to what kernel actually uses
+  struct ksigevent { void *sv; int signo, notify, tid; } kk = {
+    0, se->sigev_signo, se->sigev_notify, 0
+  };
+  int timer;
+
+  if (syscall(SYS_timer_create, c, &kk, &timer)<0) return -1;
+  *t = (timer_t)(long)timer;
+
+  return 0;
+}
+
+int timer_settime_wrap(timer_t t, int flags, struct itimerspec *val,
+  struct itimerspec *old)
+{
+  return syscall(SYS_timer_settime, t, flags, val, old);
+}
 #endif

lib/portability.h

@@ -387,4 +387,11 @@ struct itimerspec {
 };
 int timer_create(clock_t c, struct sigevent *se, timer_t *t);
 int timer_settime(timer_t t, int flags, struct itimerspec *new, void *old);
+#elif !CFG_TOYBOX_HASTIMERS
+#include <syscall.h>
+int timer_create_wrap(clockid_t c, struct sigevent *se, timer_t *t);
+#define timer_create(...) timer_create_wrap(__VA_ARGS__)
+int timer_settime_wrap(timer_t t, int flags, struct itimerspec *val,
+  struct itimerspec *old);
+#define timer_settime(...) timer_settime_wrap(__VA_ARGS__)
 #endif

scripts/genconfig.sh

@@ -9,14 +9,14 @@ source scripts/portability.sh
 
 probecc()
 {
-  ${CROSS_COMPILE}${CC} $CFLAGS -xc -o /dev/null $1 -
+  ${CROSS_COMPILE}${CC} $CFLAGS $LDFLAGS -xc -o /dev/null - "$@"
 }
 
 # Probe for a single config symbol with a "compiles or not" test.
 # Symbol name is first argument, flags second, feed C file to stdin
 probesymbol()
 {
-  probecc $2 2>/dev/null && DEFAULT=y || DEFAULT=n
+  probecc "${@:2}" 2>/dev/null && DEFAULT=y || DEFAULT=n
   rm a.out 2>/dev/null
   echo -e "config $1\n\tbool" || exit 1
   echo -e "\tdefault $DEFAULT\n" || exit 1
@@ -112,6 +112,11 @@ EOF
     #include <sys/syscall.h>
     #include <unistd.h>
     int main(void) { copyfilerange(0, 0, 1, 0, 123, 0); }
+EOF
+  probesymbol TOYBOX_HASTIMERS -lrt << EOF
+    #include <signal.h>
+    #include <time.h>
+    int main(void) {void *x=0;timer_create(CLOCK_MONOTONIC,x,x);}
 EOF
 }