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
    2 0x6bc20c in agg::agg_graphics::~agg_graphics() ../src/agg/agg_graphics.cpp:96
    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
    6 0x6789b7 in process_gobs ../src/os/linux/host-compositor.c:559
    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
    17 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    18 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    19 0x419332 in Do_Next ../src/core/c-do.c:886
    20 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    21 0x4a6c9a in N_do ../src/core/n-control.c:524
    22 0x43e037 in Do_Native ../src/core/c-function.c:289
    23 0x419332 in Do_Next ../src/core/c-do.c:886
    24 0x41b643 in Try_Block ../src/core/c-do.c:1087
    25 0x4a872e in N_try ../src/core/n-control.c:760
    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
    33 0x4190d4 in Do_Next ../src/core/c-do.c:879
    34 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    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
    40 0x4a6c9a in N_do ../src/core/n-control.c:524
    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
    46 0x419332 in Do_Next ../src/core/c-do.c:886
    47 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    48 0x4a732e in N_either ../src/core/n-control.c:598
    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
    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
    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
    2 0x664b61 in RXD_Draw ../src/os/host-draw.c:438
    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
    6 0x678500 in process_gobs ../src/os/linux/host-compositor.c:520
    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
    17 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    18 0x419332 in Do_Next ../src/core/c-do.c:886
    19 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    20 0x43f6c8 in Do_Function ../src/core/c-function.c:415
    21 0x419332 in Do_Next ../src/core/c-do.c:886
    22 0x41aaed in Do_Blk ../src/core/c-do.c:1017
    23 0x4a6c9a in N_do ../src/core/n-control.c:524
    24 0x43e037 in Do_Native ../src/core/c-function.c:289
    25 0x419332 in Do_Next ../src/core/c-do.c:886
    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)