libs: don't rely on sane global environment

some addons like to provide a broken _G variable to
the global environment breaking every other addon that
relies on it if existing. With this commit, make ShaguTweaks
no longer re-use the global _G, even if existing.

libs/libcast.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local L = ShaguTweaks.L
 local GetExpansion = ShaguTweaks.GetExpansion
 local libtipscan = ShaguTweaks.libtipscan

libs/libdebuff.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local L = ShaguTweaks.L
 local GetExpansion = ShaguTweaks.GetExpansion
 local libtipscan = ShaguTweaks.libtipscan

libs/libhealth.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local L = ShaguTweaks.L
 local GetExpansion = ShaguTweaks.GetExpansion
 

libs/libnameplate.lua

@@ -1,4 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
 local GetExpansion = ShaguTweaks.GetExpansion
 local GetUnitData = ShaguTweaks.GetUnitData
 

libs/libpredict.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local L = ShaguTweaks.L
 local GetExpansion = ShaguTweaks.GetExpansion
 local libtipscan = ShaguTweaks.libtipscan

libs/libspell.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local GetExpansion = ShaguTweaks.GetExpansion
 local libtipscan = ShaguTweaks.libtipscan
 local hooksecurefunc = ShaguTweaks.hooksecurefunc

libs/libtipscan.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local libtipscan = {}
 local baseName = "ShaguTweaksTooltip"
 local methods = {

libs/libunitscan.lua

@@ -1,5 +1,4 @@
-local _G = _G or getfenv(0)
+local _G = ShaguTweaks.GetGlobalEnv()
-
 local GetExpansion = ShaguTweaks.GetExpansion
 local L = ShaguTweaks.L