Using "yum-builddep" misses packages that are in the RPMs ifdef conditionals

Issue

• By default, yum-builddep misses packages that are in conditionals. The yum-builddep command is documented to "install missing dependencies for building an RPM package", and it even goes so far to use the "kernel" package in its examples. However, yum-builddep misses packages in BuildRequires: lines that are in conditionals. For example, using the example command causes the subsequent rpmbuild -bb kernel.spec to fail due to the following missed dependencies.

     error: Failed build dependencies:
             pesign >= 0.109-4 is needed by kernel-3.10.0-123.1.2.el7.x86_64
             elfutils-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             zlib-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             binutils-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             newt-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             python-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             perl(ExtUtils::Embed) is needed by kernel-3.10.0-123.1.2.el7.x86_64
             bison is needed by kernel-3.10.0-123.1.2.el7.x86_64
             audit-libs-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             numactl-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             pciutils-devel is needed by kernel-3.10.0-123.1.2.el7.x86_64
             gettext is needed by kernel-3.10.0-123.1.2.el7.x86_64