Add some tricks into HACKING.

* README: Typo.
* HACKING: s/CVS/GIT/ and add some tricks about libtool and doxygen.

ChangeLog

+2011-02-08  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Add some tricks into HACKING.
+
+	* README: Typo.
+	* HACKING: s/CVS/GIT/ and add some tricks about libtool and doxygen.
+
 2011-02-08  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	Adjust the WDBA test to count for sub-transitions.

HACKING

-Bootstraping from CVS:
+Bootstraping from GIT:
 ======================
 
 Some files in SPOT's source tree are generated.  They are distributed
 so that users do not need to tools to rebuild them, but we don't keep
-all of them under CVS because it can generate lots of changes or
+all of them under GIT because it can generate lots of changes or
 conflicts.
 
-Here are the tools you need to bootstrap the CVS tree, or more
+Here are the tools you need to bootstrap the GIT tree, or more
 generally if you plan to regenerate some of the generated files.
 
   GNU Autoconf >= 2.61
@@ -17,7 +17,7 @@ generally if you plan to regenerate some of the generated files.
   SWIG >= 1.3.31
   Doxygen >= 1.4.0
 
-Bootstrap the CVS tree by running
+Bootstrap the GIT tree by running
 
   autoreconf -vfi
 
@@ -27,6 +27,69 @@ and then go on with the usual
   make
 
 
+Tricks
+======
+
+Avoiding Doxygen runs
+---------------------
+
+When there is no documentation built (e.g., after a fresh checkout
+of the GIT tree), when the configure.ac file has changed, or when
+the Doxygen configuration has changed, the doc will be rebuilt.
+
+This can take quite some time, even though recent version of Doxygen
+have started to parallelize things.  If you have no interest
+in generating the documentation, just use the "magic touch":
+
+  touch doc/stamp
+
+Do that right before running make.  The timestamp of doc/stamp
+is compared to configure.ac and Doxygen.in to decide if the
+documentation is out-of-date.  The above command pretends the
+documentation has just been built.
+
+
+Debugging Libtool executables
+-----------------------------
+
+The executable generated in the various testsuite directories of Spot,
+are not real binaries.  Because we use libtool to compile the spot
+library in a portable manner, these executable are just script that
+run the actual binary after setting some environment variable so that
+the OS can find the library in the build tree.
+
+A consequence is that tools like gdb or valgrind, that expect to
+work on a binary, will be confused by the script.  Example:
+
+  % cd src/tgbatest
+  % file ltl2tgba
+  ltl2tgba: POSIX shell script text executable
+  % gdb -q ltl2tgba
+  "/home/adl/git/spot/src/tgbatest/ltl2tgba": not in executable format: File format not recognized
+  (gdb) quit
+
+The proper way to work on these libtool scripts is via the libtool
+command:
+
+  % ../../libtool --mode=execute file ltl2tgba
+  /home/adl/git/spot/src/tgbatest/.libs/lt-ltl2tgba: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
+  % ../../libtool --mode=execute gdb -q ltl2tgba
+  Reading symbols from /home/adl/git/spot/src/tgbatest/.libs/lt-ltl2tgba...done.
+  (gdb) quit
+
+If you are building Spot from the GIT repository the libtool script
+generated the root of the build tree should be the same as the libtool
+script that is installed on your system.  So you can simply run
+libtool instead of ../../libtool.
+
+You might also find conveniant to define a alias, a function, or a
+script to shorten the invocation of "libtool --mode=execute".
+
+Also there is an undocumented feature of libtool that allows you to
+shorthand "libtool --mode=execute" as "libtool execute" or even
+"libtool e".
+
+
 Coding conventions:
 ===================
 

README

@@ -22,8 +22,8 @@ later).  Especially, Python's headers files should be installed.
 
 Spot also uses modified versions of BuDDy (a binary decision diagram),
 and LBTT (an LTL to Büchi test bench).  You do not need to install
-these yourself, they are included in this package (directories buddy/
-and lbtt/), and will built and installed alongside of Spot.
+these yourself: they are included in this package (directories buddy/
+and lbtt/) and will be built and installed alongside of Spot.
 
 
 Building and installing
@@ -33,7 +33,7 @@ Spot follows the traditional `./configure && make && make check &&
 make install' process.  People unfamiliar with the GNU Build System
 should read the file INSTALL for generic instructions.
 
-In additions to its usual options, ./configure will accept some
+In addition to its usual options, ./configure will accept some
 flags specific to Spot:
 
   --with-gspn=DIR