diff --git a/winsup/configure.ac b/winsup/configure.ac
index 59b77fe3ed..bacff0b794 100644
--- a/winsup/configure.ac
+++ b/winsup/configure.ac
@@ -57,6 +57,40 @@ AC_CHECK_TOOL(RANLIB, ranlib, ranlib)
 AC_CHECK_TOOL(STRIP, strip, strip)
 AC_CHECK_TOOL(WINDRES, windres, windres)
 
+# Record msys2-runtime commit
+AC_ARG_WITH([msys2-runtime-commit],
+  [AS_HELP_STRING([--with-msys2-runtime-commit=COMMIT],
+		  [indicate the msys2-runtime commit corresponding to this build])],
+  [MSYS2_RUNTIME_COMMIT=$withval], [MSYS2_RUNTIME_COMMIT=yes])
+case "$MSYS2_RUNTIME_COMMIT" in
+no)
+    MSYS2_RUNTIME_COMMIT=
+    MSYS2_RUNTIME_COMMIT_SHORT=
+    MSYS2_RUNTIME_COMMIT_HEX=0
+    ;;
+yes|auto)
+    if MSYS2_RUNTIME_COMMIT="$(git --git-dir="$srcdir/../.git" rev-parse HEAD)"
+    then
+        MSYS2_RUNTIME_COMMIT_SHORT="$(expr "$MSYS2_RUNTIME_COMMIT" : '\(.\{,8\}\)')"
+        MSYS2_RUNTIME_COMMIT_HEX="0x${MSYS2_RUNTIME_COMMIT_SHORT}ul"
+    else
+        AC_MSG_WARN([Could not determine msys2-runtime commit"])
+        MSYS2_RUNTIME_COMMIT=
+        MSYS2_RUNTIME_COMMIT_SHORT=
+        MSYS2_RUNTIME_COMMIT_HEX=0
+    fi
+    ;;
+*)
+    expr "$MSYS2_RUNTIME_COMMIT" : '@<:@0-9a-f@:>@\{6,64\}$' ||
+    AC_MSG_ERROR([Invalid commit name: "$MSYS2_RUNTIME_COMMIT"])
+    MSYS2_RUNTIME_COMMIT_SHORT="$(expr "$MSYS2_RUNTIME_COMMIT" : '\(.\{,8\}\)')"
+    MSYS2_RUNTIME_COMMIT_HEX="0x${MSYS2_RUNTIME_COMMIT_SHORT}ul"
+    ;;
+esac
+AC_SUBST(MSYS2_RUNTIME_COMMIT)
+AC_SUBST(MSYS2_RUNTIME_COMMIT_SHORT)
+AC_SUBST(MSYS2_RUNTIME_COMMIT_HEX)
+
 AC_ARG_ENABLE(debugging,
 [AS_HELP_STRING([--enable-debugging],[Build a cygwin DLL which has more consistency checking for debugging])],
 [case "${enableval}" in
diff --git a/winsup/cygwin/Makefile.am b/winsup/cygwin/Makefile.am
index ec782dc6b9..a7607b0d67 100644
--- a/winsup/cygwin/Makefile.am
+++ b/winsup/cygwin/Makefile.am
@@ -17,6 +17,11 @@ if TARGET_X86_64
 COMMON_CFLAGS+=-mcmodel=small
 endif
 
+VERSION_CFLAGS = -DMSYS2_RUNTIME_COMMIT="\"@MSYS2_RUNTIME_COMMIT@\""
+VERSION_CFLAGS += -DMSYS2_RUNTIME_COMMIT_SHORT="\"@MSYS2_RUNTIME_COMMIT_SHORT@\""
+VERSION_CFLAGS += -DMSYS2_RUNTIME_COMMIT_HEX="@MSYS2_RUNTIME_COMMIT_HEX@"
+COMMON_CFLAGS += $(VERSION_CFLAGS)
+
 AM_CFLAGS=$(cflags_common) $(COMMON_CFLAGS)
 AM_CXXFLAGS=$(cxxflags_common) $(COMMON_CFLAGS) -fno-threadsafe-statics
 
@@ -439,7 +444,7 @@ uname_version.c: .FORCE
 version.cc: scripts/mkvers.sh include/cygwin/version.h winver.rc $(src_files)
 	@echo "Making version.cc and winver.o";\
 	export CC="$(CC)";\
-	/bin/sh $(word 1,$^) $(word 2,$^) $(word 3,$^) $(WINDRES) $(CFLAGS)
+	/bin/sh $(word 1,$^) $(word 2,$^) $(word 3,$^) $(WINDRES) $(CFLAGS) $(VERSION_CFLAGS)
 
 winver.o: version.cc
 
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 41e62ff235..84a1cda498 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -530,7 +530,7 @@ get_cygwin_startup_info ()
   child_info *res = (child_info *) si.lpReserved2;
 
   if (si.cbReserved2 < EXEC_MAGIC_SIZE || !res
-      || res->intro != PROC_MAGIC_GENERIC || res->magic != CHILD_INFO_MAGIC)
+      || res->intro != PROC_MAGIC_GENERIC || res->magic != (CHILD_INFO_MAGIC ^ MSYS2_RUNTIME_COMMIT_HEX))
     {
       strace.activate (false);
       res = NULL;
diff --git a/winsup/cygwin/scripts/mkvers.sh b/winsup/cygwin/scripts/mkvers.sh
index 98826f8fc9..60586adf94 100755
--- a/winsup/cygwin/scripts/mkvers.sh
+++ b/winsup/cygwin/scripts/mkvers.sh
@@ -16,6 +16,7 @@ incfile="$1"; shift
 rcfile="$1"; shift
 windres="$1"; shift
 iflags=
+msys2_runtime_commit=
 # Find header file locations
 while [ -n "$*" ]; do
   case "$1" in
@@ -26,6 +27,9 @@ while [ -n "$*" ]; do
     shift
     iflags="$iflags -I$1"
       ;;
+  -DMSYS2_RUNTIME_COMMIT=*)
+    msys2_runtime_commit="${1#*=}"
+    ;;
   esac
   shift
 done
@@ -168,6 +172,10 @@ then
   cvs_tag="$(echo $wv_cvs_tag | sed -e 's/-branch.*//')"
   cygwin_ver="$cygwin_ver-$cvs_tag"
 fi
+if [ -n "$msys2_runtime_commit" ]
+then
+  cygwin_ver="$cygwin_ver-$msys2_runtime_commit"
+fi
 
 echo "Version $cygwin_ver"
 set -$- $builddate
diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index fd3291c1bc..3d3f38fef9 100644
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -811,7 +811,7 @@ int child_info::retry_count = 0;
 child_info::child_info (unsigned in_cb, child_info_types chtype,
 			bool need_subproc_ready):
   msv_count (0), cb (in_cb), intro (PROC_MAGIC_GENERIC),
-  magic (CHILD_INFO_MAGIC), type (chtype), cygheap (::cygheap),
+  magic (CHILD_INFO_MAGIC ^ MSYS2_RUNTIME_COMMIT_HEX), type (chtype), cygheap (::cygheap),
   cygheap_max (::cygheap_max), flag (0), retry (child_info::retry_count),
   rd_proc_pipe (NULL), wr_proc_pipe (NULL), sigmask (_my_tls.sigmask)
 {
diff --git a/winsup/cygwin/uname.cc b/winsup/cygwin/uname.cc
index a4ac0e304d..a978363f1c 100644
--- a/winsup/cygwin/uname.cc
+++ b/winsup/cygwin/uname.cc
@@ -76,18 +76,19 @@ uname_x (struct utsname *name)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-truncation="
 #ifdef CYGPORT_RELEASE_INFO
-      snprintf (name->release, _UTSNAME_LENGTH, "%s.%s",
-		__XSTRING (CYGPORT_RELEASE_INFO), name->machine);
+      snprintf (name->release, _UTSNAME_LENGTH, "%s-%s.%s",
+		__XSTRING (CYGPORT_RELEASE_INFO), MSYS2_RUNTIME_COMMIT_SHORT, name->machine);
 #else
       extern const char *uname_dev_version;
       if (uname_dev_version && uname_dev_version[0])
-	snprintf (name->release, _UTSNAME_LENGTH, "%s.%s",
-		  uname_dev_version, name->machine);
+	snprintf (name->release, _UTSNAME_LENGTH, "%s-%s.%s",
+		  uname_dev_version, MSYS2_RUNTIME_COMMIT_SHORT, name->machine);
       else
-	__small_sprintf (name->release, "%d.%d.%d-api-%d.%s",
+	__small_sprintf (name->release, "%d.%d.%d-%s-api-%d.%s",
 			 cygwin_version.dll_major / 1000,
 			 cygwin_version.dll_major % 1000,
 			 cygwin_version.dll_minor,
+			 MSYS2_RUNTIME_COMMIT_SHORT,
 			 cygwin_version.api_minor,
 			 name->machine);
 #endif
@@ -129,14 +130,15 @@ uname (struct utsname *in_name)
       cygwin_gethostname (name->nodename, sizeof (name->nodename) - 1);
 
       /* Cygwin dll release */
-      __small_sprintf (name->release, "%d.%d.%d(%d.%d/%d/%d)",
+      __small_sprintf (name->release, "%d.%d.%d(%d.%d/%d/%d/%s)",
 		       cygwin_version.dll_major / 1000,
 		       cygwin_version.dll_major % 1000,
 		       cygwin_version.dll_minor,
 		       cygwin_version.api_major,
 		       cygwin_version.api_minor,
 		       cygwin_version.shared_data,
-		       cygwin_version.mount_registry);
+		       cygwin_version.mount_registry,
+		       MSYS2_RUNTIME_COMMIT_SHORT);
 
       /* Cygwin "version" aka build date */
       strcpy (name->version, cygwin_version.dll_build_date);