Added a filter to transform the sky130_ml_xx_hd library from
metal1 to metal5 and scale the characters up by a factor of 12
so that they will be DRC clean for metal5.

sky130/Makefile.in

diff --git a/sky130/Makefile.in b/sky130/Makefile.in
index aab678b..a33c113 100644
--- a/sky130/Makefile.in
+++ b/sky130/Makefile.in
@@ -513,7 +513,7 @@
 	${RM} ${STAGING_PATH}/${SKY130A}/libs.ref/sky130_fd_sc_lp/verilog/*.*.v
 	# Install alphanumeric library.
 	${STAGE} -source ${REPO_PATH} -target ${STAGING_PATH}/${SKY130A} \
-		-mag %l/mag/*.mag \
+		-mag %l/mag/*.mag filter=custom/scripts/text2m5.py \
 		-library general sky130_ml_xx_hd |& tee -a ${SKY130A}_install.log
 	# Install text2mag.py script for alphanumeric library
 	mkdir -p ${STAGING_PATH}/${SKY130A}/libs.ref/sky130_ml_xx_hd/scripts

sky130/custom/scripts/text2m5.py

diff --git a/sky130/custom/scripts/text2m5.py b/sky130/custom/scripts/text2m5.py
new file mode 100755
index 0000000..05b8750
--- /dev/null
+++ b/sky130/custom/scripts/text2m5.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+#
+# text2m5 ---
+#
+# This script changes magic layouts from the sky130_ml_xx_hd library
+# by recasting the layer used from metal1 to metal5, and adding a
+# scalefactor of 12 so that the characters are sized to avoid DRC
+# errors on metal5.
+#
+# This script is a filter to be run by setting the name of this script as
+# the value to "filter=" for the library install in the sky130 Makefile.
+
+import re
+import os
+import sys
+
+def filter(inname, outname):
+
+    # Read input
+    try:
+        with open(inname, 'r') as inFile:
+            spitext = inFile.read()
+            spilines = spitext.splitlines()
+    except:
+        print('text2m5.py: failed to open ' + fnmIn + ' for reading.', file=sys.stderr)
+        return 1
+
+    # Process input with regexp
+
+    fixedlines = []
+    modified = False
+
+    for line in spilines:
+
+        # These substitutions are for files originating from cells/*/*.spice
+        fixedline = re.sub('<< metal1 >>', '<< metal5 >>', line)
+        fixedline = re.sub('tech sky130A', 'tech sky130A\nmagscale 12 1', fixedline)
+
+        fixedlines.append(fixedline)
+        if fixedline != line:
+            modified = True
+
+    # Write output
+    if outname == None:
+        for i in fixedlines:
+            print(i)
+    else:
+        # If the output is a symbolic link but no modifications have been made,
+        # then leave it alone.  If it was modified, then remove the symbolic
+        # link before writing.
+        if os.path.islink(outname):
+            if not modified:
+                return 0
+            else:
+                os.unlink(outname)
+        try:
+            with open(outname, 'w') as outFile:
+                for i in fixedlines:
+                    print(i, file=outFile)
+        except:
+            print('text2m5.py: failed to open ' + outname + ' for writing.', file=sys.stderr)
+            return 1
+
+
+if __name__ == '__main__':
+
+    # This script expects to get one or two arguments.  One argument is
+    # mandatory and is the input file.  The other argument is optional and
+    # is the output file.  The output file and input file may be the same
+    # name, in which case the original input is overwritten.
+
+    options = []
+    arguments = []
+    for item in sys.argv[1:]:
+        if item.find('-', 0) == 0:
+            options.append(item[1:])
+        else:
+            arguments.append(item)
+
+    if len(arguments) > 0:
+        infilename = arguments[0]
+
+    if len(arguments) > 1:
+        outfilename = arguments[1]
+    else:
+        outfilename = None
+
+    result = filter(infilename, outfilename)
+    sys.exit(result)