<s>
A	O
configure	B-Device
script	I-Device
is	O
an	O
executable	O
script	O
designed	O
to	O
aid	O
in	O
developing	O
a	O
program	B-Application
to	O
be	O
run	O
on	O
a	O
wide	O
number	O
of	O
different	O
computers	O
.	O
</s>
<s>
It	O
matches	O
the	O
libraries	B-Library
on	O
the	O
user	O
's	O
computer	O
,	O
with	O
those	O
required	O
by	O
the	O
program	B-Application
before	O
compiling	B-Language
it	O
from	O
its	O
source	O
code	O
.	O
</s>
<s>
As	O
a	O
common	O
practice	O
,	O
all	O
configure	B-Device
scripts	I-Device
are	O
named	O
configure	B-Device
.	O
</s>
<s>
Usually	O
,	O
configure	B-Device
scripts	I-Device
are	O
written	O
for	O
the	B-Device
Bourne	I-Device
shell	I-Device
,	O
but	O
they	O
may	O
be	O
written	O
for	O
execution	O
in	O
any	O
desired	O
shell	O
.	O
</s>
<s>
Obtaining	O
software	O
directly	O
from	O
the	O
source	O
code	O
is	O
a	O
common	O
procedure	O
on	O
Unix	B-Application
computers	O
,	O
and	O
generally	O
involves	O
the	O
following	O
three	O
steps	O
:	O
configuring	O
the	O
makefile	O
,	O
compiling	B-Language
the	O
code	O
,	O
and	O
finally	O
installing	O
the	O
executable	O
to	O
standard	O
locations	O
.	O
</s>
<s>
A	O
configure	B-Device
script	I-Device
accomplishes	O
the	O
first	O
of	O
these	O
steps	O
.	O
</s>
<s>
Using	O
configure	B-Device
scripts	I-Device
is	O
an	O
automated	O
method	O
of	O
generating	O
makefiles	O
before	O
compilation	B-Language
to	O
tailor	O
the	O
software	O
to	O
the	O
system	O
on	O
which	O
the	O
executable	O
is	O
to	O
be	O
compiled	B-Language
and	O
run	O
.	O
</s>
<s>
One	O
must	O
type	O
./configure	O
rather	O
than	O
simply	O
configure	B-Device
to	O
indicate	O
to	O
the	O
shell	O
that	O
the	O
script	O
is	O
in	O
the	O
current	O
directory	O
.	O
</s>
<s>
This	O
is	O
because	O
,	O
as	O
a	O
security	O
precaution	O
,	O
Unix	B-Application
configurations	O
do	O
n't	O
search	O
the	O
current	O
directory	O
for	O
executables	O
.	O
</s>
<s>
Upon	O
its	O
completion	O
,	O
configure	B-Device
prints	O
a	O
report	O
to	O
config.log	O
.	O
</s>
<s>
Running	O
./configure	O
--help	O
gives	O
a	O
list	O
of	O
command	O
line	O
arguments	O
,	O
for	O
enabling	O
or	O
disabling	O
additional	O
features	O
such	O
as	O
:	O
</s>
<s>
The	O
first	O
line	O
includes	O
the	O
mpfr	O
and	O
gmp	O
libraries	B-Library
.	O
</s>
<s>
The	O
second	O
line	O
tells	O
make	B-Application
to	O
install	O
the	O
final	O
version	O
in	O
/home/user/local	O
.	O
</s>
<s>
This	O
can	O
be	O
helpful	O
if	O
configure	B-Device
fails	O
.	O
</s>
<s>
Software	O
developers	O
simplify	O
the	O
challenge	O
of	O
cross-platform	B-Operating_System
software	I-Operating_System
development	O
by	O
using	O
GNU	B-Application
Autotools	I-Application
.	O
</s>
<s>
They	O
store	O
the	O
gathered	O
information	O
in	O
configure.ac	O
or	O
the	O
now	O
deprecated	O
configure.in	O
to	O
be	O
read	O
by	O
configure	B-Device
during	O
the	O
installation	O
phase	O
.	O
</s>
<s>
In	O
new	O
development	O
,	O
library	O
dependency	O
checking	O
has	O
been	O
done	O
in	O
great	O
part	O
using	O
pkg-config	B-Application
via	O
the	O
m4	B-Device
macro	O
,	O
PKG_CHECK_MODULES	O
.	O
</s>
<s>
Before	O
pkg-config	B-Application
gained	O
popularity	O
,	O
separate	O
m4	B-Device
macros	I-Device
were	O
created	O
to	O
locate	O
files	O
known	O
to	O
be	O
included	O
in	O
the	O
distribution	O
of	O
libraries	B-Library
depended	O
upon	O
.	O
</s>
<s>
The	O
first	O
program	B-Application
to	O
come	O
with	O
a	O
configure	B-Device
script	I-Device
was	O
rn	B-Protocol
by	O
Larry	O
Wall	O
in	O
1984	O
.	O
</s>
<s>
It	O
still	O
survives	O
as	O
part	O
of	O
the	O
build	O
system	O
of	O
the	O
trn	O
program	B-Application
.	O
</s>
<s>
Since	O
then	O
,	O
an	O
ecosystem	O
of	O
programs	O
has	O
grown	O
up	O
to	O
automate	O
the	O
creation	O
of	O
configure	B-Device
scripts	I-Device
as	O
far	O
as	O
possible	O
,	O
of	O
which	O
the	O
most	O
common	O
is	O
the	O
GNU	B-Application
Autoconf	I-Application
system	O
.	O
</s>
