diff --git a/tools/winebuild/spec32.c b/tools/winebuild/spec32.c
index 70527425b60..d008f08530d 100644
--- a/tools/winebuild/spec32.c
+++ b/tools/winebuild/spec32.c
@@ -629,8 +629,18 @@ void BuildSpec32File( FILE *outfile )
                  "    extern char **__wine_main_argv;\n"
                  "    STARTUPINFOA info;\n"
                  "    char *cmdline = GetCommandLineA();\n"
-                 "    while (*cmdline && *cmdline != ' ') cmdline++;\n"
-                 "    if (*cmdline) cmdline++;\n"
+                 "    int bcount=0, in_quotes=0;\n"
+                 "    while (*cmdline) {\n"
+                 "        if ((*cmdline=='\\t' || *cmdline==' ') && !in_quotes) break;\n"
+                 "        else if (*cmdline=='\\\\') bcount++;\n"
+                 "        else if (*cmdline=='\\\"') {\n"
+                 "            if ((bcount & 1)==0) in_quotes=!in_quotes;\n"
+                 "            bcount=0;\n"
+                 "        }\n"
+                 "        else bcount=0;\n"
+                 "        cmdline++;\n"
+                 "    }\n"
+                 "    while (*cmdline=='\\t' || *cmdline==' ') cmdline++;\n"
                  "    GetStartupInfoA( &info );\n"
                  "    if (!(info.dwFlags & 1)) info.wShowWindow = 1;\n"
                  "    _ARGC = __wine_main_argc;\n"
@@ -666,8 +676,18 @@ void BuildSpec32File( FILE *outfile )
                  "    extern WCHAR **__wine_main_wargv;\n"
                  "    STARTUPINFOA info;\n"
                  "    char *cmdline = GetCommandLineA();\n"
-                 "    while (*cmdline && *cmdline != ' ') cmdline++;\n"
-                 "    if (*cmdline) cmdline++;\n"
+                 "    int bcount=0, in_quotes=0;\n"
+                 "    while (*cmdline) {\n"
+                 "        if ((*cmdline=='\\t' || *cmdline==' ') && !in_quotes) break;\n"
+                 "        else if (*cmdline=='\\\\') bcount++;\n"
+                 "        else if (*cmdline=='\\\"') {\n"
+                 "            if ((bcount & 1)==0) in_quotes=!in_quotes;\n"
+                 "            bcount=0;\n"
+                 "        }\n"
+                 "        else bcount=0;\n"
+                 "        cmdline++;\n"
+                 "    }\n"
+                 "    while (*cmdline=='\\t' || *cmdline==' ') cmdline++;\n"
                  "    GetStartupInfoA( &info );\n"
                  "    if (!(info.dwFlags & 1)) info.wShowWindow = 1;\n"
                  "    _ARGC = __wine_main_argc;\n"