Add 'press g to attach gdb' feature

Action.c

@@ -392,6 +392,24 @@ static Htop_Reaction actionStrace(State* st) {
    return HTOP_REFRESH | HTOP_REDRAW_BAR;
 }
 
+static Htop_Reaction actionGdb(State* st) {
+   Process* p = (Process*) Panel_getSelected(st->panel);
+   if (!p) return HTOP_OK;
+
+   char buf[32];
+   xSnprintf(buf, sizeof(buf), "gdb -p %d", (int) p->pid);
+
+   endwin();
+   int result = system(buf);
+   refresh();
+
+   // we don't really care about the invocation result
+   (void) result;
+
+   CRT_enableDelay();
+   return HTOP_REFRESH | HTOP_REDRAW_BAR;
+}
+
 static Htop_Reaction actionTag(State* st) {
    Process* p = (Process*) Panel_getSelected(st->panel);
    if (!p) return HTOP_OK;
@@ -437,6 +455,7 @@ static const struct { const char* key; const char* info; } helpRight[] = {
    { .key = "      i: ", .info = "set IO priority" },
    { .key = "      l: ", .info = "list open files with lsof" },
    { .key = "      s: ", .info = "trace syscalls with strace" },
+   { .key = "      g: ", .info = "debug with gdb" },
    { .key = "         ", .info = "" },
    { .key = " F2 C S: ", .info = "setup" },
    { .key = "   F1 h: ", .info = "show this help screen" },
@@ -588,6 +607,7 @@ void Action_setBindings(Htop_Action* keys) {
    keys[KEY_F(2)] = actionSetup;
    keys['l'] = actionLsof;
    keys['s'] = actionStrace;
+   keys['g'] = actionGdb;
    keys[' '] = actionTag;
    keys['\014'] = actionRedraw; // Ctrl+L
    keys[KEY_F(1)] = actionHelp;

htop.1.in

@@ -101,6 +101,9 @@ update of system calls issued by the process.
 .B l
 Display open files for a process: if lsof(1) is installed, pressing this key
 will display the list of file descriptors opened by the process.
+.B g
+Debug process: if gdb(1) is installed, pressing this key will attach it
+to the currently selected process, allowing you to debug it.
 .TP
 .B F1, h, ?
 Go to the help screen