Fix an alloc-dealloc-mismatch

Found by GCC Address Sanitizer:

=================================================================
==32465==ERROR: AddressSanitizer: alloc-dealloc-mismatch (malloc vs operator delete []) on 0x6030000add40
    #0 0x7f012194676f in operator delete[](void*) (/usr/lib/libasan.so.1+0x5876f)
    #1 0x6c8785 in agg::agg_graphics::agg_reset() ../src/agg/agg_graphics.cpp:1562
    rebolsource#2 0x6bc20c in agg::agg_graphics::~agg_graphics() ../src/agg/agg_graphics.cpp:96
    rebolsource#3 0x66fb18 in rebdrw_gob_draw ../src/os/host-draw-api-agg.cpp:571
    #4 0x678500 in process_gobs ../src/os/linux/host-compositor.c:520
    #5 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    rebolsource#6 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    rebol#7 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    #8 0x67b63f in rebcmp_compose ../src/os/linux/host-compositor.c:685
    #9 0x65158c in Draw_Window ../src/os/host-view.c:225
    #10 0x651b21 in Show_Gob ../src/os/host-view.c:288
    #11 0x6520ed in RXD_Graphics ../src/os/host-view.c:346
    #12 0x471ccd in Do_Command ../src/core/f-extension.c:456
    #13 0x419332 in Do_Next ../src/core/c-do.c:886
    #14 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #15 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    #16 0x419332 in Do_Next ../src/core/c-do.c:886
    rebol#17 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #18 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    rebol#19 0x419332 in Do_Next ../src/core/c-do.c:886
    #20 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#21 0x4a6c9a in N_do ../src/core/n-control.c:524
    rebol#22 0x43e037 in Do_Native ../src/core/c-function.c:289
    rebol#23 0x419332 in Do_Next ../src/core/c-do.c:886
    #24 0x41b643 in Try_Block ../src/core/c-do.c:1087
    rebol#25 0x4a872e in N_try ../src/core/n-control.c:760
    rebol#26 0x43e037 in Do_Native ../src/core/c-function.c:289
    #27 0x419332 in Do_Next ../src/core/c-do.c:886
    #28 0x4168bd in Do_Args ../src/core/c-do.c:668
    #29 0x41a070 in Do_Next ../src/core/c-do.c:942
    #30 0x4168bd in Do_Args ../src/core/c-do.c:668
    #31 0x4190d4 in Do_Next ../src/core/c-do.c:879
    #32 0x4168bd in Do_Args ../src/core/c-do.c:668
    rebol#33 0x4190d4 in Do_Next ../src/core/c-do.c:879
    #34 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#35 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    #36 0x419332 in Do_Next ../src/core/c-do.c:886
    #37 0x4168bd in Do_Args ../src/core/c-do.c:668
    #38 0x4190d4 in Do_Next ../src/core/c-do.c:879
    #39 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#40 0x4a6c9a in N_do ../src/core/n-control.c:524
    rebol#41 0x43e037 in Do_Native ../src/core/c-function.c:289
    #42 0x419332 in Do_Next ../src/core/c-do.c:886
    #43 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #44 0x4a732e in N_either ../src/core/n-control.c:598
    #45 0x43e037 in Do_Native ../src/core/c-function.c:289
    rebol#46 0x419332 in Do_Next ../src/core/c-do.c:886
    #47 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#48 0x4a732e in N_either ../src/core/n-control.c:598
    rebol#49 0x43e037 in Do_Native ../src/core/c-function.c:289
    #50 0x419332 in Do_Next ../src/core/c-do.c:886
    #51 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #52 0x4a732e in N_either ../src/core/n-control.c:598
    rebol#53 0x43e037 in Do_Native ../src/core/c-function.c:289
    #54 0x419332 in Do_Next ../src/core/c-do.c:886
    #55 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #56 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    #57 0x42094d in Apply_Function ../src/core/c-do.c:1528
    #58 0x42116c in Do_Sys_Func ../src/core/c-do.c:1588
    #59 0x426d54 in Init_Mezz ../src/core/c-do.c:2320
    rebol#60 0x4069c1 in RL_Start ../src/core/a-lib.c:193
    #61 0x5fea9d in main ../src/os/host-main.c:235
    #62 0x7f011fed27ff in __libc_start_main (/usr/lib/libc.so.6+0x207ff)
    #63 0x405dd8 in _start (/home/zsx/stuffs/work/r3.git/make/r3-view-linux+0x405dd8)

0x6030000add40 is located 0 bytes inside of 24-byte region [0x6030000add40,0x6030000add58)
allocated by thread T0 here:
    #0 0x7f01219457a7 in malloc (/usr/lib/libasan.so.1+0x577a7)
    #1 0x606495 in OS_Make ../src/os/linux/host-lib.c:380
    rebolsource#2 0x664b61 in RXD_Draw ../src/os/host-draw.c:438
    rebolsource#3 0x472f24 in Do_Commands ../src/core/f-extension.c:585
    #4 0x4073a0 in RL_Do_Commands ../src/core/a-lib.c:402
    #5 0x66fadb in rebdrw_gob_draw ../src/os/host-draw-api-agg.cpp:568
    rebolsource#6 0x678500 in process_gobs ../src/os/linux/host-compositor.c:520
    rebol#7 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    #8 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    #9 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    #10 0x67b63f in rebcmp_compose ../src/os/linux/host-compositor.c:685
    #11 0x65158c in Draw_Window ../src/os/host-view.c:225
    #12 0x651b21 in Show_Gob ../src/os/host-view.c:288
    #13 0x6520ed in RXD_Graphics ../src/os/host-view.c:346
    #14 0x471ccd in Do_Command ../src/core/f-extension.c:456
    #15 0x419332 in Do_Next ../src/core/c-do.c:886
    #16 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#17 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    #18 0x419332 in Do_Next ../src/core/c-do.c:886
    rebol#19 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    #20 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    rebol#21 0x419332 in Do_Next ../src/core/c-do.c:886
    rebol#22 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    rebol#23 0x4a6c9a in N_do ../src/core/n-control.c:524
    #24 0x43e037 in Do_Native ../src/core/c-function.c:289
    rebol#25 0x419332 in Do_Next ../src/core/c-do.c:886
    rebol#26 0x41b643 in Try_Block ../src/core/c-do.c:1087
    #27 0x4a872e in N_try ../src/core/n-control.c:760
    #28 0x43e037 in Do_Native ../src/core/c-function.c:289
    #29 0x419332 in Do_Next ../src/core/c-do.c:886

SUMMARY: AddressSanitizer: alloc-dealloc-mismatch ??:0 operator delete[](void*)
==32465==HINT: if you don't care about these warnings you may set ASAN_OPTIONS=alloc_dealloc_mismatch=0
==32465==ABORTING

src/os/host-draw-api-agg.cpp

@@ -291,7 +291,15 @@ namespace agg
 
 	extern "C" void rebdrw_line_pattern(void* gr, REBCNT col, REBDEC* patterns)
 	{
-        ((agg_graphics*)gr)->agg_line_pattern((col) ? (REBYTE*)&col : NULL, patterns);
+		/* convert malloc'ed memory to new'ed memory */
+		REBDEC * new_patterns = NULL;
+		if (patterns != NULL) {
+			size_t len = patterns[0];
+			new_patterns = new REBDEC[len + 1];
+			memcpy(new_patterns, patterns, (len + 1) * sizeof(REBDEC));
+			free(patterns);
+		}
+        ((agg_graphics*)gr)->agg_line_pattern((col) ? (REBYTE*)&col : NULL, new_patterns);
 	}
 
 	extern "C" void rebdrw_line_width(void* gr, REBDEC width, REBINT mode)