diff --git a/headers/build/BeOSBuildCompatibility.h b/headers/build/BeOSBuildCompatibility.h
index 398f34267c..23d39ce48e 100644
--- a/headers/build/BeOSBuildCompatibility.h
+++ b/headers/build/BeOSBuildCompatibility.h
@@ -1,6 +1,22 @@
 #ifndef BEOS_BUILD_COMPATIBILITY_H
 #define BEOS_BUILD_COMPATIBILITY_H
 
+#if defined(HAIKU_HOST_PLATFORM_CYGWIN)
+#ifndef __addr_t_defined
+#define __addr_t_defined
+#endif
+
+#ifndef DEFFILEMODE
+#define DEFFILEMODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
+#endif
+
+#ifndef S_IUMSK
+#define	S_IUMSK 07777
+#endif
+
+#include <ctype.h>
+#endif
+
 typedef unsigned long haiku_build_addr_t;
 #define addr_t haiku_build_addr_t
 
@@ -27,6 +43,11 @@ extern size_t	strlcat(char *dest, const char *source, size_t length);
 extern size_t	strnlen(const char *string, size_t length);
 #endif
 
+#if defined(HAIKU_HOST_PLATFORM_CYGWIN)
+extern char * stpcpy(char *dest, const char *src);
+extern char * strcasestr(const char *s, const char *find);
+#endif
+
 // BeOS only
 extern ssize_t  read_pos(int fd, off_t pos, void *buffer, size_t count);
 extern ssize_t  write_pos(int fd, off_t pos, const void *buffer, size_t count);
@@ -62,7 +83,6 @@ extern char *_haiku_build_strerror(int errnum);
 
 #endif
 
-
 #ifdef __cplusplus
 } // extern "C"
 #endif
diff --git a/src/build/libroot/Jamfile b/src/build/libroot/Jamfile
index fcf5731de2..f57629fbb7 100644
--- a/src/build/libroot/Jamfile
+++ b/src/build/libroot/Jamfile
@@ -27,6 +27,10 @@ if $(HOST_PLATFORM) != darwin {
 	strlSources = strlcpy.c strlcat.c ;
 }
 
+if $(HOST_PLATFORM) = cygwin {
+	strlSources += stpcpy.c strcasestr.c ;
+}
+
 local hostPlatformSources ;
 if $(HOST_PLATFORM) = freebsd {
 	hostPlatformSources = fs_freebsd.cpp ;
diff --git a/src/build/libroot/errors.cpp b/src/build/libroot/errors.cpp
index 30871dbbaf..3b34c97a74 100644
--- a/src/build/libroot/errors.cpp
+++ b/src/build/libroot/errors.cpp
@@ -75,7 +75,9 @@ init_error_map()
 	ADD_ERROR(ENOTSOCK);
 	ADD_ERROR(EHOSTDOWN);
 	ADD_ERROR(EBADMSG);
-	ADD_ERROR(ECANCELED);
+	#ifdef ECANCELED
+		ADD_ERROR(ECANCELED);
+	#endif
 	ADD_ERROR(EDESTADDRREQ);
 	ADD_ERROR(EDQUOT);
 	ADD_ERROR(EIDRM);