Add Non-Windows build product to gitignore
Fix unused variable / value warnings when building with clang

    fs.c:3175:37: warning: expression result unused [-Wunused-value]
                    for (i = 0; i < bytes_read1; i++, bytes_total) {
                                                      ^~~~~~~~~~~

    EX_browser_ping.c:347:11: warning: unused variable 'arg' [-Wunused-variable]
        u_int arg;
              ^

    cl_demo.c:3157:8: warning: unused variable 'asp' [-Wunused-variable]
            float asp = 0;
                  ^

    gl_rmain.c:1529:16: warning: unused variable 'gl_hwblend' [-Wunused-variable]
            extern cvar_t gl_hwblend;
                          ^
Fix lots of leaks with call stacks under QTVList_Process_Full_List XML_ParseBuffer

Leak: 0x7f862c047000  size=1536  zone: DefaultMallocZone_0x105748000
	0x00000000 0x00000000 0x00000400 0x6c6d7468 	............html
	0x6d780000 0x00736e6c 0x6c6d7800 0x6e616c3a 	..xmlns..xml:lan
	0x6c000067 0x00676e61 0x64616568 0x74656d00 	g..lang.head.met
	0x68000061 0x2d707474 0x69757165 0x63000076 	a..http-equiv..c
	0x65746e6f 0x7400746e 0x656c7469 0x6e696c00 	ontent.title.lin
	0x7200006b 0x00006c65 0x66657268 0x79740000 	k..rel..href..ty
	0x00006570 0x6c746974 0x6f620065 0x6f007964 	pe..title.body.o
	0x63656a62 0x64000074 0x00617461 0x79747300 	bject..data..sty
	...
	Call stack: [thread 0x10c6a0000]:
        | thread_start
        | _pthread_struct_init
        | _pthread_body
        | RunThread
        | SDL_RunThread
        | QTVList_Refresh_Cache_Thread EX_browser_qtvlist.c:475
        | QTVList_Refresh_Cache EX_browser_qtvlist.c:382
        | QTVList_Process_Full_List EX_browser_qtvlist.c:267
        | XML_ParseBuffer
        | prologProcessor
        | doProlog
        | contentProcessor
        | doContent
        | storeAtts
        | poolCopyString
        | poolGrow
        | malloc
        | malloc_zone_malloc
Fix lots of leaks with call stacks under sv_mod_msg_file_OnChange

When using the built-in list of qw messages there is no need for allocation.
The alloc was immediately leaked when we point to the built-in message.

Also, there already exists a mechanism (qwm_static) to avoid accidentally
attempting to free the built-in messages if the file changes.

Leak: 0x7fd3f254b560  size=32  zone: DefaultMallocZone_0x1107c9000
	0x00000000 0x00000000 0x00000000 0x00000000 	................
	0x00000000 0x00000000 0x00000000 0x00000000 	................
	Call stack: [thread 0x7fff79ffb310]:
        | 0x1
        | start
        | main sys_posix.c:310
        | Host_Init host.c:625
        | Cvar_Set cvar.c:310
        | sv_mod_msg_file_OnChange sv_mod_frags.c:67
        | Q_malloc q_shared.c:884
        | malloc
        | malloc_zone_malloc
Fix lots of leaks with call stacks under HUD_Register

HUD_CreateVar was duping the name and string value and calling Cvar_Register.
However, Cvar_Register looks like it will always dup the string value. Avoid
the extra duplicate in HUD_CreateVar and all the leaks go away.

Leak: 0x7fd7e0710740  size=16  zone: DefaultMallocZone_0x10815f000  "gameclock"
	Call stack: [thread 0x7fff79ffb310]:
        | 0x1
        | start
        | main sys_posix.c:310
        | Host_Init host.c:608
        | CL_Init cl_main.c:2042
        | HUD_Init hud.c:1527
        | CommonDraw_Init hud_common.c:7322
        | HUD_Register hud.c:1139
        | Q_strdup q_shared.c:916
        | strdup
        | malloc
        | malloc_zone_malloc

This removes 1098 leaks on launch bringing us down to 1.

    Before: Process 4335: 1099 leaks for 18528 total leaked bytes.
    After:  Process 4957: 1 leak for 816 total leaked bytes.