Make FFTW flags "public" (#329)

* Make FFTW flags "public"

* make all flags public

* Limit public to v11 and beyond

* Isolate public assertions in public.jl

* Use @static and eval

Author: JeffFessler

src/FFTW.jl

@@ -14,6 +14,24 @@ import AbstractFFTs: Plan, ScaledPlan,
 
 export dct, idct, dct!, idct!, plan_dct, plan_idct, plan_dct!, plan_idct!
 
+# FFTW flags from fft.jl
+@static if VERSION ≥ v"1.11.0"
+    eval(Expr(
+        :public,
+        :MEASURE,
+        :DESTROY_INPUT,
+        :UNALIGNED,
+        :CONSERVE_MEMORY,
+        :EXHAUSTIVE,
+        :PRESERVE_INPUT,
+        :PATIENT,
+        :ESTIMATE,
+        :WISDOM_ONLY,
+        :NO_SIMD,
+    ))
+end
+
+
 include("providers.jl")
 
 function fftw_init_check()