Add GPL guards for CHOLMOD usage to make Enzyme.jl GPL-safe (#2650)

This commit adds `@static if Base.USE_GPL_LIBS` guards around all
CHOLMOD-related dispatches in Enzyme.jl. This ensures that when Julia
is built without GPL libraries, Enzyme.jl remains license-compatible.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: ChrisRackauckas <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: 3 people

src/absint.jl

@@ -608,7 +608,12 @@ function abs_typeof(
             # add the extra poitner offset when loading here]. However for pointers constructed by ccall outside julia
             # to a julia object, which are not inline by type but appear so, like SparseArrays, this is a problem
             # and merits further investigation. x/ref https://github.com/EnzymeAD/Enzyme.jl/issues/2085
-            if !Base.allocatedinline(typ) && typ != SparseArrays.cholmod_dense_struct && typ != SparseArrays.cholmod_sparse_struct && typ != SparseArrays.cholmod_factor_struct
+            @static if Base.USE_GPL_LIBS
+                cholmod_exception = typ != SparseArrays.cholmod_dense_struct && typ != SparseArrays.cholmod_sparse_struct && typ != SparseArrays.cholmod_factor_struct
+            else
+                cholmod_exception = true
+            end
+            if !Base.allocatedinline(typ) && cholmod_exception
                 shouldLoad = false
                 offset %= sizeof(Int)
             else

src/analyses/activity.jl

@@ -19,7 +19,9 @@ end
 @inline ptreltype(::Type{Tuple{Vararg{T}}}) where {T} = T
 @inline ptreltype(::Type{IdDict{K,V}}) where {K,V} = V
 @inline ptreltype(::Type{IdDict{K,V} where K}) where {V} = V
+@static if Base.USE_GPL_LIBS
 @inline ptreltype(::Type{SparseArrays.CHOLMOD.Dense{T}}) where T = T
+end
 @static if VERSION < v"1.11-"
 else
 @inline ptreltype(::Type{Memory{T}}) where T = T
@@ -33,7 +35,9 @@ end
 @inline is_arrayorvararg_ty(::Type{Base.RefValue{T}}) where {T} = true
 @inline is_arrayorvararg_ty(::Type{IdDict{K,V}}) where {K,V} = true
 @inline is_arrayorvararg_ty(::Type{IdDict{K,V} where K}) where {V} = true
+@static if Base.USE_GPL_LIBS
 @inline is_arrayorvararg_ty(::Type{SparseArrays.CHOLMOD.Dense{T}}) where T = true
+end
 @static if VERSION < v"1.11-"
 else
 @inline is_arrayorvararg_ty(::Type{Memory{T}}) where T = true