diff --git a/winsup/configure.ac b/winsup/configure.ac
index ca2b8c0748..cfb0bbf279 100644
--- a/winsup/configure.ac
+++ b/winsup/configure.ac
@@ -57,6 +57,34 @@ 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_HEX=0
+    ;;
+yes|auto)
+    if MSYS2_RUNTIME_COMMIT="$(git --git-dir="$srcdir/../.git" rev-parse HEAD)"
+    then
+        MSYS2_RUNTIME_COMMIT_HEX="0x$(expr "$MSYS2_RUNTIME_COMMIT" : '\(.\{,8\}\)')ull"
+    else
+        AC_MSG_WARN([Could not determine msys2-runtime commit"])
+        MSYS2_RUNTIME_COMMIT=
+        MSYS2_RUNTIME_COMMIT_HEX=0
+    fi
+    ;;
+*)
+    expr "$MSYS2_RUNTIME_COMMIT" : '@<:@0-9a-f@:>@\{6,64\}$' ||
+    AC_MSG_ERROR([Invalid commit name: "$MSYS2_RUNTIME_COMMIT"])
+    MSYS2_RUNTIME_COMMIT_HEX="0x$(expr "$MSYS2_RUNTIME_COMMIT" : '\(.\{,8\}\)')ull"
+    ;;
+esac
+AC_SUBST(MSYS2_RUNTIME_COMMIT_HEX)
+
 AC_ARG_ENABLE(debugging,
 [ --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 01666e1cf4..695ebeb7c7 100644
--- a/winsup/cygwin/Makefile.am
+++ b/winsup/cygwin/Makefile.am
@@ -17,6 +17,9 @@ if TARGET_X86_64
 COMMON_CFLAGS+=-mcmodel=small
 endif
 
+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
 
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 45f3b0f905..d354eab7dc 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -545,7 +545,7 @@ 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 ^ CYGWIN_VERSION_DLL_COMBINED))
+      || res->intro != PROC_MAGIC_GENERIC || res->magic != (CHILD_INFO_MAGIC ^ MSYS2_RUNTIME_COMMIT_HEX))
     {
       strace.activate (false);
       res = NULL;
diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index 65dc523ca5..782c0d97cd 100644
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -817,7 +817,7 @@ int child_info::retry_count = 0;
    by fork/spawn/exec. */
 child_info::child_info (unsigned in_cb, child_info_types chtype,
 			bool need_subproc_ready):
-  cb (in_cb), intro (PROC_MAGIC_GENERIC), magic (CHILD_INFO_MAGIC ^ CYGWIN_VERSION_DLL_COMBINED),
+  cb (in_cb), intro (PROC_MAGIC_GENERIC), 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)