Compiling GDB in another directory
==================================
If you want to run GDB versions for several host or target machines,
you need a different `gdb' compiled for each combination of host and
target. `configure' is designed to make this easy by allowing you to
generate each configuration in a separate subdirectory, rather than in
the source directory. If your `make' program handles the `VPATH'
feature (GNU `make' does), running `make' in each of these directories
builds the `gdb' program specified there.
To build `gdb' in a separate directory, run `configure' with the
`--srcdir' option to specify where to find the source. (You also need
to specify a path to find `configure' itself from your working
directory. If the path to `configure' would be the same as the
argument to `--srcdir', you can leave out the `--srcdir' option; it is
assumed.)
For example, with version 2002-04-01-cvs, you can build GDB in a
separate directory for a Sun 4 like this:
cd gdb-2002-04-01-cvs
mkdir ../gdb-sun4
cd ../gdb-sun4
../gdb-2002-04-01-cvs/configure sun4
make
When `configure' builds a configuration using a remote source
directory, it creates a tree for the binaries with the same structure
(and using the same names) as the tree under the source directory. In
the example, you'd find the Sun 4 library `libiberty.a' in the
directory `gdb-sun4/libiberty', and GDB itself in `gdb-sun4/gdb'.
One popular reason to build several GDB configurations in separate
directories is to configure GDB for cross-compiling (where GDB runs on
one machine--the "host"--while debugging programs that run on another
machine--the "target"). You specify a cross-debugging target by giving
the `--target=TARGET' option to `configure'.
When you run `make' to build a program or library, you must run it
in a configured directory--whatever directory you were in when you
called `configure' (or one of its subdirectories).
The `Makefile' that `configure' generates in each source directory
also runs recursively. If you type `make' in a source directory such
as `gdb-2002-04-01-cvs' (or in a separate configured directory
configured with `--srcdir=DIRNAME/gdb-2002-04-01-cvs'), you will build
all the required libraries, and then build GDB.
When you have multiple hosts or targets configured in separate
directories, you can run `make' on them in parallel (for example, if
they are NFS-mounted on each of the hosts); they will not interfere
with each other.