Added locking to debug output, to prevent race condition between threads

configure.ac

@@ -24,8 +24,8 @@ dnl Checks for typedefs, structures and compiler characteristics
 
 AC_CANONICAL_HOST
 
-AC_CHECK_LIB([m], [main])
-AC_CHECK_LIB([pthread], [main])
+AC_CHECK_LIB([m], [main], [], [echo "Failed to find lib!" ; exit -1])
+AC_CHECK_LIB([pthread], [main], [], [echo "Failed to find lib!" ; exit -1])
 
 with_sdr=no
 soapy_0_7_1_or_higher=

src/libdebug/debug.c

@@ -25,6 +25,7 @@
 #include <errno.h>
 #include <math.h>
 #include <time.h>
+#include <pthread.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
 #include "debug.h"
@@ -100,6 +101,9 @@ void (*print_console_text)(void) = NULL;
 
 int debug_limit_scroll = 0;
 
+static int lock_initialized = 0;
+static pthread_mutex_t debug_mutex;
+
 void get_win_size(int *w, int *h)
 {
 	struct winsize win;
@@ -123,10 +127,22 @@ void _printdebug(const char *file, const char __attribute__((unused)) *function,
 	const char *p;
 	va_list args;
 	int w, h;
+	int rc;
 
 	if (debuglevel > level)
 		return;
 
+	if (!(debug_mask & ((uint64_t)1 << cat)))
+		return;
+
+	if (!lock_initialized) {
+		rc = pthread_mutex_init(&debug_mutex, NULL);
+		if (rc == 0)
+			lock_initialized = 1;
+	}
+	if (lock_initialized)
+		pthread_mutex_lock(&debug_mutex);
+
 	buffer[sizeof(buffer) - 1] = '\0';
 
 	/* if kanal is used, prefix the channel number */
@@ -136,9 +152,6 @@ void _printdebug(const char *file, const char __attribute__((unused)) *function,
 		s -= strlen(buffer);
 	}
 
-	if (!(debug_mask & ((uint64_t)1 << cat)))
-		return;
-
 	va_start(args, fmt);
 	vsnprintf(b, s, fmt, args);
 	va_end(args);
@@ -166,6 +179,9 @@ void _printdebug(const char *file, const char __attribute__((unused)) *function,
 	if (print_console_text)
 		print_console_text();
 	fflush(stdout);
+
+	if (lock_initialized)
+		pthread_mutex_unlock(&debug_mutex);
 }
 
 const char *debug_amplitude(double level)