diff --git a/auto/cc/owc b/auto/cc/owc
index 22eb4c125..a063aa341 100644
--- a/auto/cc/owc
+++ b/auto/cc/owc
@@ -65,10 +65,10 @@ have=NGX_HAVE_C99_VARIADIC_MACROS . auto/have
 
 
 # the precompiled headers
-CORE_DEPS="$CORE_DEPS $NGX_OBJS/ngx_config.pch"
-NGX_PCH="$NGX_OBJS/ngx_config.pch"
-NGX_BUILD_PCH="-fhq=$NGX_OBJS/ngx_config.pch"
-NGX_USE_PCH="-fh=$NGX_OBJS/ngx_config.pch"
+#CORE_DEPS="$CORE_DEPS $NGX_OBJS/ngx_config.pch"
+#NGX_PCH="$NGX_OBJS/ngx_config.pch"
+#NGX_BUILD_PCH="-fhq=$NGX_OBJS/ngx_config.pch"
+#NGX_USE_PCH="-fh=$NGX_OBJS/ngx_config.pch"
 
 
 # the link flags, built target is NT GUI mode application
diff --git a/auto/lib/pcre/makefile.owc b/auto/lib/pcre/makefile.owc
index 78f5257b3..122fd5b27 100644
--- a/auto/lib/pcre/makefile.owc
+++ b/auto/lib/pcre/makefile.owc
@@ -4,7 +4,7 @@
 
 
 CFLAGS =	-c -zq -bt=nt -ot -op -oi -oe -s -bm $(CPU_OPT)
-PCREFLAGS =	-DHAVE_CONFIG_H -DPCRE_STATIC -DPOSIX_MALLOC_THRESHOLD=10 \
+PCREFLAGS =	-DHAVE_CONFIG_H -DPCRE_STATIC -DPOSIX_MALLOC_THRESHOLD=10 &
 		-DSUPPORT_PCRE8 -DHAVE_MEMMOVE
 
 
diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c
index 3b392f7b2..d3ff36855 100644
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -486,7 +486,7 @@ ngx_sprintf_num(u_char *buf, u_char *last, uint64_t ui64, u_char zero,
 
     if (hexadecimal == 0) {
 
-        if (ui64 <= NGX_MAX_UINT32_VALUE) {
+        if (ui64 <= (uint64_t) NGX_MAX_UINT32_VALUE) {
 
             /*
              * To divide 64-bit numbers and to find remainders
diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
index f9281a371..680b65871 100644
--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -1129,7 +1129,7 @@ ngx_http_mp4_update_mdat_atom(ngx_http_mp4_file_t *mp4, off_t start_offset)
 
     atom_header = mp4->mdat_atom_header;
 
-    if ((uint64_t) atom_data_size > 0xffffffff) {
+    if ((uint64_t) atom_data_size > (uint64_t) 0xffffffff) {
         atom_size = 1;
         atom_header_size = sizeof(ngx_mp4_atom_header64_t);
         ngx_mp4_set_64value(atom_header + sizeof(ngx_mp4_atom_header_t),
diff --git a/src/os/win32/ngx_win32_config.h b/src/os/win32/ngx_win32_config.h
index 623569855..7face954f 100644
--- a/src/os/win32/ngx_win32_config.h
+++ b/src/os/win32/ngx_win32_config.h
@@ -128,13 +128,27 @@ typedef unsigned short int  uint16_t;
 
 typedef __int64             int64_t;
 typedef unsigned __int64    uint64_t;
+
+#ifndef __WATCOMC__
 typedef int                 intptr_t;
 typedef u_int               uintptr_t;
+#endif
+
 
 /* Windows defines off_t as long, which is 32-bit */
 typedef __int64             off_t;
 #define _OFF_T_DEFINED
 
+#ifdef __WATCOMC__
+
+/* off_t is redefined by sys/types.h used by zlib.h */
+#define __TYPES_H_INCLUDED
+typedef int                 dev_t;
+typedef unsigned int        ino_t;
+
+#endif
+
+
 typedef int                 ssize_t;
 typedef uint32_t            in_addr_t;
 typedef u_short             in_port_t;