Update Makefile

Fixed build detection to properly distinguish between Android/Termux and regular Linux environments. Android systems report as "Linux" in kernel checks but require different compiler flags and libraries.

The fix ensures:

· Android builds get Termux-compatible flags (-D__ANDROID__, iconv linking)
· Regular Linux builds get standard flags (-DWITH_HWMON)
· Proper library linking for each platform
· No flag conflicts between environments

Detection order is critical since both systems identify as Linux at kernel level.