userland: replace legacy cc with native TCC and vendor submodule

src/userland/cli/third_party/tcc/lib/armflush.c

@@ -0,0 +1,64 @@
+/* armflush.c - flush the instruction cache
+
+   __clear_cache is used in tccrun.c,  It is a built-in
+   intrinsic with gcc.  However tcc in order to compile
+   itself needs this function */
+
+/* ------------------------------------------------------------- */
+#if defined __arm__
+
+#ifdef __TINYC__
+
+/* syscall wrapper */
+unsigned _tccsyscall(unsigned syscall_nr, ...);
+
+/* arm-tcc supports only fake asm currently */
+__asm__(
+    ".global _tccsyscall\n"
+    "_tccsyscall:\n"
+    "push    {r7, lr}\n\t"
+    "mov     r7, r0\n\t"
+    "mov     r0, r1\n\t"
+    "mov     r1, r2\n\t"
+    "mov     r2, r3\n\t"
+    "svc     #0\n\t"
+    "pop     {r7, pc}"
+    );
+
+/* from unistd.h: */
+#if defined(__thumb__) || defined(__ARM_EABI__)
+# define __NR_SYSCALL_BASE      0x0
+#else
+# define __NR_SYSCALL_BASE      0x900000
+#endif
+#define __ARM_NR_BASE           (__NR_SYSCALL_BASE+0x0f0000)
+#define __ARM_NR_cacheflush     (__ARM_NR_BASE+2)
+
+#define syscall _tccsyscall
+
+#else
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <stdio.h>
+
+#endif
+
+/* Flushing for tccrun */
+void __clear_cache(void *beginning, void *end)
+{
+/* __ARM_NR_cacheflush is kernel private and should not be used in user space.
+ * However, there is no ARM asm parser in tcc so we use it for now */
+    syscall(__ARM_NR_cacheflush, beginning, end, 0);
+}
+
+/* ------------------------------------------------------------- */
+#elif defined __aarch64__
+void __clear_cache(void *beg, void *end)
+{
+    __arm64_clear_cache(beg, end);
+}
+
+/* ------------------------------------------------------------- */
+#endif