systemd: export :reload function
Makefile/run.sh.out follows ./bin/compile.sh
bin/compile.sh: remove empty lines from library files
lib/pkgbuild: change behavior of :_pkgbuild_s_sources

* It will update the $source (from PKGBUILD) variable
* The remote source will use the first character of PAKCAGE_BASE
  as a prefix. For example, pacman -> /s/p/pacman/
* It will detect if WITHOUT_THESLINUX_SOURCES environment is set.
  If yes, it simly return after printing out $source.
lib/pkgbuild/_pkgbuild_sources: remove this function

This function display an array in single column mode.
We should have a better way to do this (for all arrays.)
lib/pkgbuild#_makepkg will load #makepkg by sourcing

This is to save some resources and remove duplications
lib/pkgbuild#_pkgbuild_load invokes #_pkgbuild_s_sources

This is to update $source variable in this step immediately
lib/pkgbuild#_pkgbuild_load update comments
lib/git#_s_env set PACKAGE_* variables read-only
lib/pkgbuild#_makepkg remove duplicated assigments
lib/git#_s_env --dump option is now in a separated method #_s_env_dump
S_ENV_LOADED variable is used to prevent #_s_env to be reloaded

After (lib/git#s_env) is loaded, the variable will be set READ-ONLY.
Next invoking of (lib/git#s_env) will know if this variable is read-only
or not. If yes, the invoking simply returns 0.

Because of this, the main function (lib/zz_main) must check the variable
globally, before any invoking.

Files changes
* lib/zz_main.sh: add global check
* lib/git.sh: tune #s_env to return if it is already loaded
Makefile: validate syntax of the output Bash file
lib/pkgbuild#_pkgbuild_s_sources will not invoke #_pkgbuild_load

This will cause an infinite loop, because we have ensured that
#_pkgbuild_load invokes #_pkgbuild_s_sources. Now #_pkgbuild_s_sources
is a very internal function which may be very useless :)
lib/pkgbuild#_pkgbuild_load fix #pkgname variable

This variable should be an array. The #makepkg script assumes
this is an array, for example, in (#makepkg#check_sanity).
When "set -u" is used, (check_sanity) may fail.