Pinning answers to two often raised questions.
About pkg-config: this is part of base-devel group, which is expected to be installed on any system using the AUR. So this is not a missing dependency.
About armv7h in arch array: ArchLinux ARM is already providing cower for all arm archs, and more generally any other arch being unsupported it’s your responsibility to modify the PKGBUILD to add yours. And no, 'any' is not the same as a list of specific archs, it means that the produced binary is arch-independent, which is rarely the case.
To rebuild cower:
pacaur -S --rebuild cower