adb: don't use <error.h>.

This should fix the bloody Mac build, which doesn't have <error.h>. Since
we weren't entirely happy with error(3) anyway, switch to the toybox
style of error_exit and perror_exit, which are slightly briefer and quite
a bit more intention-revealing.

Bug: N/A
Test: builds
Change-Id: Ic8e411906c363af51657da5ce947b25a0b6bb1f3
diff --git a/adb/adb_utils.cpp b/adb/adb_utils.cpp
index bc184c5..ad77064 100644
--- a/adb/adb_utils.cpp
+++ b/adb/adb_utils.cpp
@@ -341,3 +341,33 @@
     return android::base::StringPrintf("%s/adb.%u.log", tmp_dir, getuid());
 #endif
 }
+
+[[noreturn]] static void error_exit_va(int error, const char* fmt, va_list va) {
+    fflush(stdout);
+    fprintf(stderr, "%s: ", android::base::Basename(android::base::GetExecutablePath()).c_str());
+
+    vfprintf(stderr, fmt, va);
+
+    if (error != 0) {
+        fprintf(stderr, ": %s", strerror(error));
+    }
+
+    putc('\n', stderr);
+    fflush(stderr);
+
+    exit(EXIT_FAILURE);
+}
+
+void error_exit(const char* fmt, ...) {
+    va_list va;
+    va_start(va, fmt);
+    error_exit_va(0, fmt, va);
+    va_end(va);
+}
+
+void perror_exit(const char* fmt, ...) {
+    va_list va;
+    va_start(va, fmt);
+    error_exit_va(errno, fmt, va);
+    va_end(va);
+}