Check for 'patch' in configure script

scripts/configure

diff --git a/scripts/configure b/scripts/configure
index 5e03076..4c9eda5 100755
--- a/scripts/configure
+++ b/scripts/configure
@@ -599,6 +599,7 @@
 XSCHEM_PATH
 SKY130_ML_XX_HD_PATH
 OSU_PATH
+PATCH
 MAGIC
 QFLOW_DISABLED
 OPENLANE_DISABLED
@@ -628,7 +629,6 @@
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -707,7 +707,6 @@
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -960,15 +959,6 @@
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1106,7 +1096,7 @@
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1259,7 +1249,6 @@
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -1291,7 +1280,7 @@
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-sky130-pdk=[/path/to/sky130/] --disable-sky130-pdk
                           "location of the source files for the sky130 (pdks
-                          with a pdk_info file can automatically download them
+                          with a pdk_url file can automatically download them
                           if the path is omitted)"
   --enable-klayout
                 Enable or disable klayout [default=enabled]
@@ -2128,6 +2117,49 @@
 if test -z "$MAGIC"; then
    as_fn_error $? "You need 'magic' to generate the needed various cell views." "$LINENO" 5
 fi
+# Extract the first word of "patch", so it can be a program name with args.
+set dummy patch; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_PATCH+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $PATCH in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_PATCH="$PATCH" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_PATCH="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  ;;
+esac
+fi
+PATCH=$ac_cv_path_PATCH
+if test -n "$PATCH"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PATCH" >&5
+$as_echo "$PATCH" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+if test -z "$PATCH"; then
+   as_fn_error $? "You need 'patch' to apply patches." "$LINENO" 5
+fi
 
 # Other installations (libraries or tools if applicable)
 mkdir -p ../libs
@@ -2484,7 +2516,7 @@
   $as_echo_n "(cached) " >&6
 else
 
-	for am_cv_pathless_PYTHON in python python2 python3 python3.8 python3.7 python3.6 python3.5 python3.4 python3.3 python3.2 python3.1 python3.0 python2.7  python2.6 python2.5 python2.4 python2.3 python2.2 python2.1 python2.0 none; do
+	for am_cv_pathless_PYTHON in python python2 python3  python3.9 python3.8 python3.7 python3.6 python3.5 python3.4 python3.3  python3.2 python3.1 python3.0  python2.7 python2.6 python2.5 python2.4 python2.3 python2.2 python2.1  python2.0 none; do
 	  test "$am_cv_pathless_PYTHON" = none && break
 	  prog="import sys
 # split strings by '.' and convert to numeric.  Append some zeros

scripts/configure.ac

diff --git a/scripts/configure.ac b/scripts/configure.ac
index 03866fc..df39b39 100755
--- a/scripts/configure.ac
+++ b/scripts/configure.ac
@@ -166,6 +166,10 @@
 if test -z "$MAGIC"; then
    AC_MSG_ERROR([You need 'magic' to generate the needed various cell views.])
 fi
+AC_PATH_PROG(PATCH, patch)
+if test -z "$PATCH"; then
+   AC_MSG_ERROR([You need 'patch' to apply patches.])
+fi
 
 # Other installations (libraries or tools if applicable)
 mkdir -p ../libs