Add --with-version=VERSION .

This simplifies configuration when embedding a jemalloc release into
another project's git repository.

This resolves #811.

2 files changed, 21 insertions, 6 deletions

diff --git a/INSTALL b/INSTALL
index abf3290b..125cad2b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -35,9 +35,20 @@ any of the following arguments (not a definitive list) to 'configure':
     will cause files to be installed into /usr/local/include, /usr/local/lib,
     and /usr/local/man.
 
---with-version=<major>.<minor>.<bugfix>-<nrev>-g<gid>
-    Use the specified version string rather than trying to generate one (if in
-    a git repository) or use existing the VERSION file (if present).
+--with-version=(<major>.<minor>.<bugfix>-<nrev>-g<gid>|VERSION)
+    The VERSION file is mandatory for successful configuration, and the
+    following steps are taken to assure its presence:
+    1) If --with-version=<major>.<minor>.<bugfix>-<nrev>-g<gid> is specified,
+       generate VERSION using the specified value.
+    2) If --with-version is not specified in either form and the source
+       directory is inside a git repository, try to generate VERSION via 'git
+       describe' invocations that pattern-match release tags.
+    3) If VERSION is missing, generate it with a bogus version:
+       0.0.0-0-g0000000000000000000000000000000000000000
+
+    Note that --with-version=VERSION bypasses (1) and (2), which simplifies
+    VERSION configuration when embedding a jemalloc release into another
+    project's git repository.
 
 --with-rpath=<colon-separated-rpath>
     Embed one or more library paths, so that libjemalloc can find the libraries
diff --git a/configure.ac b/configure.ac
index 462f509f..7ffdbea8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1349,10 +1349,14 @@ AC_ARG_WITH([version],
    [Version string])],
   [
     echo "${with_version}" | grep ['^[0-9]\+\.[0-9]\+\.[0-9]\+-[0-9]\+-g[0-9a-f]\+$'] 2>&1 1>/dev/null
-    if test $? -ne 0 ; then
-      AC_MSG_ERROR([${with_version} does not match <major>.<minor>.<bugfix>-<nrev>-g<gid>])
+    if test $? -eq 0 ; then
+      echo "$with_version" > "${objroot}VERSION"
+    else
+      echo "${with_version}" | grep ['^VERSION$'] 2>&1 1>/dev/null
+      if test $? -ne 0 ; then
+        AC_MSG_ERROR([${with_version} does not match <major>.<minor>.<bugfix>-<nrev>-g<gid> or VERSION])
+      fi
     fi
-    echo "$with_version" > "${objroot}VERSION"
   ], [
     dnl Set VERSION if source directory is inside a git repository.
     if test "x`test ! \"${srcroot}\" && cd \"${srcroot}\"; git rev-parse --is-inside-work-tree 2>/dev/null`" = "xtrue" ; then