academic/root: do not download and use gtest

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

academic/root/README

@@ -17,4 +17,20 @@ Compilation takes quite a while, thus consider to build ROOT like that:
 
 REQUIREMENTS: gl2ps libAfterImage python3-numpy tbb ftgl
 
-NOTE: ROOT's python TMVA requires python3-numpy built over blas.
+NOTES:
+  - ROOT's python TMVA requires python3-numpy being built over blas.
+
+  - This SlackBuild sets the root7 build option to ON in order to
+    prepare the migration to the new ROOT 7 release. More on the ROOT 7
+    features you can find here:
+        https://root.cern/for_developers/root7
+
+  - Starting from ROOT version 6.26/00 it uses the web-based version for
+    the TBrowser if it is build with the root7 option being ON. You can
+    switch back to the Win95-looking TBrowser by adding the following
+    line to your $HOME/.rootrc file:
+        Browser.Name: TRootBrowser
+
+  - Starting from ROOT 6.28/00 version, one can use rootssh script for
+    automatic configuration of ssh tunnel, necessary for web widgets:
+        rootssh username@remotenode

academic/root/root.SlackBuild

@@ -90,6 +90,7 @@ cmake ../src \
   -Dbuiltin_davix=OFF \
   -Dbuiltin_fftw3=OFF \
   -Dbuiltin_gsl=OFF \
+  -Dbuiltin_gtest=OFF \
   -Dbuiltin_openssl=OFF \
   -Dbuiltin_tbb=OFF \
   -Dbuiltin_vc=OFF \