default datadir does not obey the PREFIX makeflag.

[gottaeat]

Describe the bug

binary of the latest stable release looks for the game data under /usr/share/cataclysm-dda even if PREFIX is set to something other than /usr during make.

Steps To Reproduce

1. build and install with:
   make ZLEVELS=1 RELEASE=1 LOCALIZE=0 BACKTRACE=0 USE_XDG_DIR=1 PREFIX="/opt/cataclysm-dda-0.e"
2. simply run the catacylsm under $PREFIX/bin/.

Expected behavior

for the game to look under $(PREFIX)/share/catacylsm-dda instead of /usr/share/catacylsm-dda by default.

Versions and configuration

• OS: x86_64 musl linux host
• Game Version: 0.E (source obtained from here)
• Graphics version: ncurses
• Ingame language: english but not relevant
• Mods loaded: none

[gottaeat]

interestingly, i rebuilt using with these flags instead, and it automatically looked at /opt/cataclysm-dda-0.e/share/cataclysm-dda for game data:

make \
 LUA=1         \
 ASTYLE=0      \
 ZLEVELS=1     \
 RELEASE=1     \
 LOCALIZE=0    \
 BACKTRACE=0   \
 USE_XDG_DIR=1 \
 LUA_BINARY="/usr/bin/lua5.2"    \
 PREFIX="/opt/cataclysm-dda-0.e"

[anothersimulacrum]

This is the relevant area of code main.cpp:148-179.

[gottaeat]

i've rebuilt once more with my original makeflag setup and it seems that i messed something up because it does look at the correct path for datadir.

i sincerely apologize.