DOC: Better PAM tool building documentation.

For #20.

README_SETUP.md

@@ -9,13 +9,14 @@
 * >=Make 3.81
 * >=Screen 4.01
 * >=MySQL 5.5 (better >=5.6) or >=MariaDB 10.1
+* libpam (if PAM authentication is required)
 * unzip
 
 ### Install the requirements on Debian
 On Debian, the required packages can be installed with:
 
     apt-get install git make mariadb-server maven openjdk-8-jdk-headless \
-      python3-pip screen unzip
+      python3-pip screen libpam0g-dev unzip
 
 Note that installing MariaDB will uninstall existing MySQL packages and vice
 versa.
@@ -34,6 +35,23 @@ versa.
 - Then configure and compile it according to its
   [documentation](caosdb-webui/README_SETUP.md).
 
+### PAM ###
+Authentication via PAM is possible, for this the PAM development library must be
+installed and the pam user tool must be compiled:
+
+- `cd misc/pam_authentication/`
+- `make`
+- If you want, you can run a test now: `./pam_authentication.sh asdf ghjk`
+  should print `[FAILED]` and return with a non-zero exit code.  Unless there is
+  a user `asdf` with password `ghjk` on your system, of course.
+
+#### Troubleshooting ####
+If `make` fails with `pam_authentication.c:4:31: fatal error:
+security/pam_appl.h: No such file or directory` the header files are probably
+not installed. You can do so under Debian and Ubuntu with `apt-get install
+libpam0g-dev`. Then try again.
+
+
 # First Setup
 
 After a fresh clone of the repository, this is what you need to setup the

misc/pam_authentication/README.md

-# Requirements
-- pam development files: In Debian install with `apt-get install libpam0g-dev`.
+# Documentation for pam has moved #
 
-# Install
-
-`$ make`
-
-## Troubleshooting
-
-* If `make` fails with `pam_authentication.c:4:31: fatal error:
-  security/pam_appl.h: No such file or directory` the header files are probably
-  not installed. You can do so under Debian and Ubuntu with `apt-get install
-  libpam0g-dev`. Then try again.
-
-# Run Tests
-
-`$ pam_authentication.sh asdf asdf` should print `[FAILED]` and return with a
-non-zero exit code.
+Please look at the main [`README_SETUP.md`](file:../../README_SETUP.md) for
+installation help.