Revert "Update BLAS.vendor() to return :lbt"

This reverts commit e54b04a.

base/Base.jl

@@ -161,10 +161,6 @@ end
 include(strcat((length(Core.ARGS)>=2 ? Core.ARGS[2] : ""), "build_h.jl")) # include($BUILDROOT/base/build_h.jl)
 include(strcat((length(Core.ARGS)>=2 ? Core.ARGS[2] : ""), "version_git.jl")) # include($BUILDROOT/base/version_git.jl)
 
-# These used to be in build_h.jl and are retained for backwards compatibility
-const libblas_name = "libblastrampoline"
-const liblapack_name = "libblastrampoline"
-
 # numeric operations
 include("hashing.jl")
 include("rounding.jl")

stdlib/LinearAlgebra/src/blas.jl

@@ -79,8 +79,6 @@ using LinearAlgebra: BlasReal, BlasComplex, BlasFloat, BlasInt, DimensionMismatc
 
 include("lbt.jl")
 
-vendor() = :lbt
-
 """
  get_config()
 
@@ -91,6 +89,17 @@ Return an object representing the current `libblastrampoline` configuration.
 """
 get_config() = lbt_get_config()
 
+# We hard-lock `vendor()` to `openblas(64)` here to satisfy older code, but all new code should use
+# `get_config()` since it is now possible to have multiple vendors loaded at once.
+function vendor()
+ Base.depwarn("`vendor()` is deprecated, use `BLAS.get_config()` and inspect the output instead", :vendor; force=true)
+ if USE_BLAS64
+ return :openblas64
+ else
+ return :openblas
+ end
+end
+
 if USE_BLAS64
  macro blasfunc(x)
  return Expr(:quote, Symbol(x, "64_"))