Split FFTW3 into double and float versions for ROOT and O2 (alisw#5363)

* Split FFTW3 into double and float versions for ROOT and O2

ROOT requires libfftw3, but O2 requires libfftw3f.

Also, make sure that ROOT actually finds libfftw3 and doesn't just disable the
feature we request.

* Combine fftw3 and fftw3f libraries into one package

fftw3.sh

@@ -9,44 +9,25 @@ build_requires:
   - "GCC-Toolchain:(?!osx)"
 ---
 #!/bin/bash -e
-export FFTW3_WITH_AVX # use AVX with float or double. Unset automatically for long double and quad
+# ROOT and O2 need different variants of fftw3, but we cannot configure fftw3
+# to build both at the same time. As a workaround, configure and build one,
+# then wipe out the build directory and configure and build the second one.
 
-if [[ $FFTW3_DOUBLE == "ON" ]]; then # ensure only one option is set and AVX is disabled if necessary
-  FFTW3_FLOAT="OFF"
-  FFTW3_LONG_DOUBLE="OFF"
-elif [[ $FFTW3_LONG_DOUBLE == "ON" ]]; then
-  unset FFTW3_WITH_AVX
-  FFTW3_FLOAT="OFF"
-  FFTW3_DOUBLE="OFF"
-else # keep FLOAT default option as it was
-  FFTW3_FLOAT="ON"
-  FFTW3_DOUBLE="OFF"
-  FFTW3_LONG_DOUBLE="OFF"
-fi
+# First, build fftw3 (double precision), required by ROOT.
+cmake -S "$SOURCEDIR" -B "$BUILDDIR/fftw3"              \
+      -DCMAKE_INSTALL_PREFIX:PATH="$INSTALLROOT"        \
+      -DCMAKE_INSTALL_LIBDIR:PATH=lib
+make -C "$BUILDDIR/fftw3" ${JOBS+-j "$JOBS"}
+make -C "$BUILDDIR/fftw3" install
 
-case $ARCHITECTURE in
-    osx_arm64)
-  cmake $SOURCEDIR                                          \
-        -DCMAKE_INSTALL_PREFIX:PATH="${INSTALLROOT}"        \
-        -DCMAKE_INSTALL_LIBDIR:PATH="lib"                   \
-        -DENABLE_LONG_DOUBLE=${FFTW3_LONG_DOUBLE-OFF}       \
-        -DENABLE_FLOAT=${FFTW3_FLOAT-OFF}
-  ;;
-    *)
-  cmake $SOURCEDIR                                          \
-        -DCMAKE_INSTALL_PREFIX:PATH="${INSTALLROOT}"        \
-        -DCMAKE_INSTALL_LIBDIR:PATH="lib"                   \
-        -DENABLE_LONG_DOUBLE=${FFTW3_LONG_DOUBLE-OFF}       \
-        -DENABLE_FLOAT=${FFTW3_FLOAT-OFF}                   \
-        ${FFTW3_WITH_AVX:+-DENABLE_AVX=ON}
-  ;;
-esac
-
-make ${JOBS+-j $JOBS}
-make install
+# Now reconfigure for fftw3f (single precision float), required by O2.
+cmake -S "$SOURCEDIR" -B "$BUILDDIR/fftw3f"             \
+      -DCMAKE_INSTALL_PREFIX:PATH="$INSTALLROOT"        \
+      -DCMAKE_INSTALL_LIBDIR:PATH=lib                   \
+      -DENABLE_FLOAT=ON
+make -C "$BUILDDIR/fftw3f" ${JOBS+-j "$JOBS"}
+make -C "$BUILDDIR/fftw3f" install
 
 #Modulefile
-MODULEDIR="$INSTALLROOT/etc/modulefiles"
-MODULEFILE="$MODULEDIR/$PKGNAME"
-mkdir -p "$MODULEDIR"
-alibuild-generate-module --bin --lib > $MODULEFILE
+mkdir -p "$INSTALLROOT/etc/modulefiles"
+alibuild-generate-module --bin --lib > "$INSTALLROOT/etc/modulefiles/$PKGNAME"

root.sh

@@ -184,6 +184,10 @@ cmake $SOURCEDIR
 
 cmake --build . --target install ${JOBS+-j $JOBS}
 
+# Make sure ROOT actually found its build dependencies and didn't disable
+# features we requested. "-Dfail-on-missing=ON" would probably be better.
+[ "$("$INSTALLROOT/bin/root-config" --has-fftw3)" = yes ]
+
 # Add support for ROOT_PLUGIN_PATH envvar for specifying additional plugin search paths
 grep -v '^Unix.*.Root.PluginPath' $INSTALLROOT/etc/system.rootrc > system.rootrc.0
 cat >> system.rootrc.0 <<\EOF