Fix pluggable ecc support
    
    - Build nss in three phases
    - Phase 1: build softoken, freebl, and util with NSS_ENABLE_ECC unset
    - Phase 2: build the rest of nss (muinus bltest and fipstest) with NSS_ENABLE_ECC and NSS_ECC_MORE_THAN_SUITEB set
    - Phase 3: build bltest and fipstest with NSS_ENABLE_ECC unset as in phsae 1