The pkg-config files which are installed while building qt5 beta 1 have exactly the same file names as their qt4 counterparts. This makes it impossible to have development files for both qt4 and qt5 installed at the same time.
Here's a list of conflicting .pc files:
My proposal would be to rename these files in qt5 so that they contain '5' in their file names
|For Gerrit Dashboard: QTBUG-27137|
|39385,1||Fix linking on MinGW after the library renaming||master||qt/qtbase||Status: ABANDONED||-2||0|
|39925,2||MinGW: Don't add version number '0' to the library name||master||qt/qtbase||Status: MERGED||+2||0|