The next step is to get the closed binaries. The script device/semc/urushi/extract-files.sh does that by downloading them from the phone via adb. I no longer have Sony firmware in my phone so there's no need to connect the phone when the Cyanogenmod zip I used to flash it has the same contents, right? The below patch changes the source to the zip:

hajma@c:~/android/system-ics/device/semc/urushi$ git diff ./extract-files.sh 
diff --git a/extract-files.sh b/extract-files.sh
index f3aaa2c..192ea96 100755
--- a/extract-files.sh
+++ b/extract-files.sh
@@ -5,10 +5,11 @@ DEVICE=urushi
 
 BASE=../../../vendor/$VENDOR/$DEVICE/proprietary
 
-while getopts ":nh" options
+while getopts ":nzh" options
 do
   case $options in
     n ) NC=1 ;;
+    z ) FROMZIP=1;;
     h ) echo "Usage: `basename $0` [OPTIONS] "
         echo "  -n  No clenup"
         echo "  -h  Show this help"
@@ -27,7 +28,11 @@ for FILE in `cat proprietary-files.txt | grep -v ^# | grep -v ^$`; do
     if [ ! -d $BASE/$DIR ]; then
         mkdir -p $BASE/$DIR
     fi
-    adb pull /system/$FILE $BASE/$FILE
+    if [ "$FROMZIP" = "1" ]; then
+        unzip $2 system/$FILE -d $BASE
+    else
+        adb pull /system/$FILE $BASE/$FILE
+    fi
 done
 
 ./setup-makefiles.sh

... and more breakage:

hajma@c:~/android/system-ics$ brunch urushi
...
make: *** No rule to make target 'vendor/cm/proprietary/lib/armeabi/libjackpal-androidterm4.so', needed by 'out/target/product/urushi/system/lib/libjackpal-androidterm4.so'.  Stop.
make: *** Waiting for unfinished jobs....
target thumb C: calibrator <= hardware/ti/wlan/mac80211/ti-utils/ini.c
hajma@c:~/android/system-ics$ 

The file was supposed to be delivered with get-prebuilts:

hajma@c:~/android/system-ics/vendor/cm$ ./get-prebuilts 
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 3347k  100 3347k    0     0   175k      0  0:00:19  0:00:19 --:--:--  205k
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   178  100   178    0     0    296      0 --:--:-- --:--:-- --:--:--   295
100  551k  100  551k    0     0   373k      0  0:00:01  0:00:01 --:--:-- 1375k
Archive:  ./proprietary/Term.apk
caution: filename not matched:  lib/armeabi/libjackpal-androidterm4.so

but the Term.apk now has a newer version:

hajma@c:~/android/system-ics/vendor/cm$ unzip -l proprietary/Term.apk |grep libjackpal-androidterm
    13532  2015-04-15 08:09   lib/armeabi/libjackpal-androidterm5.so
     5648  2015-04-15 08:09   lib/mips/libjackpal-androidterm5.so
     5240  2015-04-15 08:09   lib/x86/libjackpal-androidterm5.so

I'll have a look at updating the term later, for now I'll use the zip one:

hajma@c:~/android/system-ics/vendor/cm$ mkdir -p proprietary/lib/armeabi/
hajma@c:~/android/system-ics/vendor/cm$ unzip -j ~/Downloads/cm-9.1.0-urushi.zip -d proprietary/lib/armeabi system/lib/libjackpal-androidterm4.so

external/llvm/include/llvm/ADT/PointerUnion.h:64:39: error: comparison between ‘enum llvm::PointerLikeTypeTraits::’ and ‘enum llvm::PointerLikeTypeTraits::’ [-Werror=enum-compare]
       NumLowBitsAvailable = PT1BitsAv < PT2BitsAv ? PT1BitsAv : PT2BitsAv

while everybody on the Internet just removes -Wall from the makefile, it can be fixed in a simpler manner, as it has been workarounded before apparently:

hajma@c:~/android/system-ics/external/llvm$ git diff include/llvm/ADT/PointerUnion.h 
diff --git a/include/llvm/ADT/PointerUnion.h b/include/llvm/ADT/PointerUnion.h
index 3e3f214..6450bdb 100644
--- a/include/llvm/ADT/PointerUnion.h
+++ b/include/llvm/ADT/PointerUnion.h
@@ -54,7 +54,7 @@ namespace llvm {
     static inline void *getAsVoidPointer(void *P) { return P; }
     static inline void *getFromVoidPointer(void *P) { return P; }
     enum {
-#if (__GNUC__ == 4 && __GNUC_MINOR__ == 7)
+#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
       PT1BitsAv = static_cast< int >(PointerLikeTypeTraits<PT1>::NumLowBitsAvailable),
       PT2BitsAv = static_cast< int >(PointerLikeTypeTraits<PT2>::NumLowBitsAvailable),
 #else

... and more:

In file included from system/extras/ext4_utils/output_file.c:30:0:
/usr/include/zlib.h:34:19: fatal error: zconf.h: No such file or directory
 #include "zconf.h"
                   ^
compilation terminated.

The cause is ugly and the solution is uglier.
getting closer...

Boot image: out/target/product/urushi/boot.img
error: unsupported page size 131072
device/semc/msm7x30-common/custombootimg.mk:5: recipe for target 'out/target/product/urushi/boot.img' failed
make: *** [out/target/product/urushi/boot.img] Error 255

Now this is caused by a second part of a changeset missing in the cm9.1 branch ... this changeset has to be applied.

aaaand here it is:

Package complete: /home/hajma/android/system-ics/out/target/product/urushi/cm-9-20150804-UNOFFICIAL-urushi.zip
41ef84db95dc7b24f78c8d0788fc1bcd  cm-9-20150804-UNOFFICIAL-urushi.zip

I don't dare to flash this yet though ;-)