since most of the compilation time is spent on creating the QRC bundle
and the resulting binary is quite huge, advice the `rcc` compiler to add
support for "big resources"
(cf https://doc.qt.io/qt-6/resources.html#embedding-large-files)
Also pass the env $LDFLAGS to qmake (to be able to link e.g. with mold,
which again greatly reduces the time to link the binary)
this leads to 6-10x faster time when recompiling
(Linux, gcc 12.1.1, mold 1.3.0)
BEFORE:
Clean build:
real 0m57,256s
user 1m25,869s
sys 0m40,963s
Incremental build, one file touched:
real 0m54,323s
user 0m54,012s
sys 0m2,934s
AFTER:
Clean build:
real 0m7,276s
user 0m21,001s
sys 0m37,256s
Incremental build, one file touched:
real 0m5,569s
user 0m4,850s
sys 0m0,840s
5e590056ff