README: list the development packages required to build the library

From: Bartosz Golaszewski <[email protected]>

The error messages emitted by configure when either libtool, pkg-config or autoconf-archive packages are missing on the host are not very clear and seem to cause confusion among users building the project from sources. List the required packages in the README.

Signed-off-by Bartosz Golaszewski <[email protected]>

---
Changes since v1:
- reword the part about missing libraries

 README | 5 +++++
 1 file changed, 5 insertions(+)

README +5 -1

index a6f24d1..a01cfc5 100644
@@ -34,6 +34,11 @@ BUILDING
 This is a pretty standard autotools project. The core C library does not have
 any external dependencies other than the standard C library with GNU extensions.
 
+The build system requires autotools, autoconf-archive, libtool and pkg-config
+to be installed on the host system for the basic build. Development files for
+additional libraries may be required depending on selected options. The
+configure script will report any missing additional required dependencies.
+
 The command-line tools optionally depend on libedit for the interactive feature.
 
 To build the project (including command-line utilities) run:
--

2.43.0

The error messages emitted by configure when either libtool, pkg-config or autoconf-archive packages are missing on the host are not very clear and seem to cause confusion among users building the project from sources. List the required packages in the README.