I have two blockers and not sure which one to remove. It seems to me they are contradicting each other.
[blocks B ] dev-util/pkgconf[pkg-config] ("dev-util/pkgconf[pkg-config]" is blocking dev-util/pkgconfig-0.28-r2) [blocks B ] dev-util/pkgconfig ("dev-util/pkgconfig" is blocking dev-util/pkgconf-0.9.12) >=dev-util/pkgconf-0.9.12[pkg-config,abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=dev-util/pkgconf-0.9.12[pkg-config,abi_x86_32(-),abi_x86_64(-)]) required by (virtual/pkgconfig-0-r1:0/0::gentoo, installed) (dev-util/pkgconfig-0.28-r2:0/0::gentoo, ebuild scheduled for merge) pulled in by >=dev-util/pkgconfig-0.28-r1[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=dev-util/pkgconfig-0.28-r1[abi_x86_32(-),abi_x86_64(-)]) required by (virtual/pkgconfig-0-r1:0/0::gentoo, installed) equery d dev-util/pkgconfig * These packages depend on dev-util/pkgconfig: virtual/pkgconfig-0-r1 (>=dev-util/pkgconfig-0.28-r1[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?]) equery d dev-util/pkgconf * These packages depend on dev-util/pkgconf: virtual/pkgconfig-0-r1 (>=dev-util/pkgconf-0.9.12[pkg-config,abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?]) -- Thelma