diff --git a/Utilities/cmlibarchive/CMakeLists.txt b/Utilities/cmlibarchive/CMakeLists.txt
index e95935a5b..8c10b2184 100644
--- a/Utilities/cmlibarchive/CMakeLists.txt
+++ b/Utilities/cmlibarchive/CMakeLists.txt
@@ -512,6 +512,8 @@ CHECK_TYPE_SIZE(int64_t     INT64_T)
 IF(NOT HAVE_INT64_T)
   IF(WIN32)
     SET(int64_t "__int64")
+  ELSE(WIN32)
+    SET(int64_t "long long")
   ENDIF(WIN32)
 ENDIF(NOT HAVE_INT64_T)
 #
@@ -568,9 +570,7 @@ ENDIF(NOT HAVE_UINT16_T)
 #
 CHECK_TYPE_SIZE(uint32_t    UINT32_T)
 IF(NOT HAVE_UINT32_T)
-  IF(WIN32)
-    SET(uint32_t "unsigned int")
-  ENDIF(WIN32)
+  SET(uint32_t "unsigned int")
 ENDIF(NOT HAVE_UINT32_T)
 CHECK_TYPE_SIZE(int32_t    INT32_T)
 IF(NOT HAVE_INT32_T)
@@ -581,6 +581,8 @@ CHECK_TYPE_SIZE(uint64_t    UINT64_T)
 IF(NOT HAVE_UINT64_T)
   IF(WIN32)
     SET(uint64_t "unsigned __int64")
+  ELSE(WIN32)
+    SET(uint64_t "unsigned long long")
   ENDIF(WIN32)
 ENDIF(NOT HAVE_UINT64_T)
 #
diff --git a/Utilities/cmlibarchive/build/cmake/config.h.in b/Utilities/cmlibarchive/build/cmake/config.h.in
index 9af45a06c..34dbce3c2 100644
--- a/Utilities/cmlibarchive/build/cmake/config.h.in
+++ b/Utilities/cmlibarchive/build/cmake/config.h.in
@@ -1,4 +1,7 @@
 /* config.h.  Generated from config.h.cmake by cmake configure */
+#if defined(__osf__)
+# define _OSF_SOURCE
+#endif
 
 /* Version number of bsdcpio */
 #cmakedefine BSDCPIO_VERSION_STRING "${BSDCPIO_VERSION_STRING}"
diff --git a/Utilities/cmlibarchive/libarchive/archive.h b/Utilities/cmlibarchive/libarchive/archive.h
index 9d84121bb..9b918a82b 100644
--- a/Utilities/cmlibarchive/libarchive/archive.h
+++ b/Utilities/cmlibarchive/libarchive/archive.h
@@ -37,7 +37,7 @@
  */
 #if defined(__BORLANDC__) && __BORLANDC__ >= 0x560
 # define __LA_STDINT_H <stdint.h>
-#elif !defined(__WATCOMC__) && !defined(_MSC_VER) && !defined(__INTERIX) && !defined(__BORLANDC__)
+#elif !defined(__WATCOMC__) && !defined(_MSC_VER) && !defined(__INTERIX) && !defined(__BORLANDC__) && !defined(__osf__)
 # define __LA_STDINT_H <inttypes.h>
 #endif
 
@@ -68,7 +68,11 @@
 # endif
 #else
 #include <unistd.h>  /* ssize_t, uid_t, and gid_t */
-#define __LA_INT64_T    int64_t
+#if defined(__osf__)
+#  define __LA_INT64_T    long long
+#else
+#  define __LA_INT64_T    int64_t
+#endif
 #define __LA_SSIZE_T    ssize_t
 #define __LA_UID_T  uid_t
 #define __LA_GID_T  gid_t
diff --git a/Utilities/cmlibarchive/libarchive/archive_endian.h b/Utilities/cmlibarchive/libarchive/archive_endian.h
index 067312d38..58abee6df 100644
--- a/Utilities/cmlibarchive/libarchive/archive_endian.h
+++ b/Utilities/cmlibarchive/libarchive/archive_endian.h
@@ -48,7 +48,7 @@
  */
 #if defined(__WATCOMC__) || defined(__sgi) || defined(__hpux) || defined(__BORLANDC__) || defined(__SUNPRO_C)
 #define inline
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) || defined(__osf__)
 #define inline __inline
 #endif
 
diff --git a/Utilities/cmlibarchive/libarchive/archive_entry.h b/Utilities/cmlibarchive/libarchive/archive_entry.h
index 9c7cd43ba..e85285f9d 100644
--- a/Utilities/cmlibarchive/libarchive/archive_entry.h
+++ b/Utilities/cmlibarchive/libarchive/archive_entry.h
@@ -61,7 +61,11 @@
 # endif
 #else
 # include <unistd.h>
-#define __LA_INT64_T    int64_t
+#ifdef __osf__
+#  define __LA_INT64_T    long long
+#else
+#  define __LA_INT64_T    int64_t
+#endif
 #define __LA_UID_T  uid_t
 #define __LA_GID_T  gid_t
 #define __LA_DEV_T  dev_t