fix building on Cygwin

Cygwin still doesn't support any of the backtrace functions. Also, remove a
spurious newline from a debug message.

Fixes #2993

4 files changed, 11 insertions, 18 deletions

diff --git a/src/common.cpp b/src/common.cpp
index b8270ad1..91b08824 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -70,7 +70,9 @@ static volatile bool termsize_valid;
 static rwlock_t termsize_rwlock;
 
 static char *wcs2str_internal(const wchar_t *in, char *out);
+static void debug_shared(const wchar_t msg_level, const wcstring &msg);
 
+#ifdef HAVE_BACKTRACE_SYMBOLS
 // This function produces a stack backtrace with demangled function & method names. It is based on
 // https://gist.github.com/fmela/591333 but adapted to the style of the fish project.
 static const wcstring_list_t __attribute__((noinline))
@@ -104,7 +106,6 @@ demangled_backtrace(int max_frames, int skip_levels) {
     return backtrace_text;
 }
 
-static void debug_shared(const wchar_t msg_level, const wcstring &msg);
 void __attribute__((noinline)) show_stackframe(const wchar_t msg_level, int frame_count,
                                                int skip_levels) {
     ASSERT_IS_NOT_FORKED_CHILD();
@@ -124,6 +125,14 @@ void __attribute__((noinline)) show_stackframe(const wchar_t msg_level, int fram
     }
 }
 
+#else // HAVE_BACKTRACE_SYMBOLS
+
+void __attribute__((noinline)) show_stackframe(const wchar_t msg_level, int frame_count,
+                                               int skip_levels) {
+    debug_shared(msg_level, L"Sorry, but your system does not support backtraces");
+}
+#endif // HAVE_BACKTRACE_SYMBOLS
+
 int fgetws2(wcstring *s, FILE *f) {
     int i = 0;
     wint_t c;
diff --git a/src/exec.cpp b/src/exec.cpp
index afd09f6a..aefdbc12 100644
--- a/src/exec.cpp
+++ b/src/exec.cpp
@@ -1058,7 +1058,7 @@ void exec_job(parser_t &parser, job_t *j) {
 
                     // A 0 pid means we failed to posix_spawn. Since we have no pid, we'll never get
                     // told when it's exited, so we have to mark the process as failed.
-                    debug(2, L"Fork #%d, pid %d: spawn external command '%s' from '%ls'\n",
+                    debug(2, L"Fork #%d, pid %d: spawn external command '%s' from '%ls'",
                           g_fork_count, pid, actual_cmd, file ? file : L"<no file>");
                     if (pid == 0) {
                         job_mark_process_as_failed(j, p);
diff --git a/src/fallback.cpp b/src/fallback.cpp
index 96fa417b..dc5bcce2 100644
--- a/src/fallback.cpp
+++ b/src/fallback.cpp
@@ -332,14 +332,6 @@ int killpg(int pgr, int sig) {
 }
 #endif
 
-#ifndef HAVE_BACKTRACE
-int backtrace(void **buffer, int size) { return 0; }
-#endif
-
-#ifndef HAVE_BACKTRACE_SYMBOLS_FD
-char **backtrace_symbols_fd(void *const *buffer, int size, int fd) { return 0; }
-#endif
-
 #ifndef HAVE_NAN
 double nan(char *tagp) { return 0.0 / 0.0; }
 #endif
diff --git a/src/fallback.h b/src/fallback.h
index a3143f09..f167ff69 100644
--- a/src/fallback.h
+++ b/src/fallback.h
@@ -149,12 +149,4 @@ int killpg(int pgr, int sig);
 double nan(char *tagp);
 #endif
 
-#ifndef HAVE_BACKTRACE
-int backtrace(void **buffer, int size);
-#endif
-
-#ifndef HAVE_BACKTRACE_SYMBOLS_FD
-char **backtrace_symbols_fd(void *const *buffer, int size, int fd);
-#endif
-
 #endif