cmake: cuba needs a -fPIC flag explicitly, otherwise it doesn't link with all compilers.

src/external/libCuba/src/common/CMakeLists.txt

@@ -25,3 +25,7 @@ target_compile_definitions(
   common PRIVATE ${COMP_DEF}
 )
 
+#--- set compiler options -----------------------------------------------------
+target_compile_options(
+  common PRIVATE -fPIC
+)

src/external/libCuba/src/cuhre/CMakeLists.txt

@@ -23,3 +23,7 @@ target_compile_definitions(
   cuhre PRIVATE ${COMP_DEF}
 )
 
+#--- set compiler options -----------------------------------------------------
+target_compile_options(
+  cuhre PRIVATE -fPIC
+)

src/external/libCuba/src/divonne/CMakeLists.txt

@@ -23,4 +23,7 @@ target_compile_definitions(
   divonne PRIVATE ${COMP_DEF}
 )
 
-
+#--- set compiler options -----------------------------------------------------
+target_compile_options(
+  divonne PRIVATE -fPIC
+)

src/external/libCuba/src/suave/CMakeLists.txt

@@ -23,3 +23,7 @@ target_compile_definitions(
   suave PRIVATE ${COMP_DEF}
 )
 
+#--- set compiler options -----------------------------------------------------
+target_compile_options(
+  suave PRIVATE -fPIC
+)

src/external/libCuba/src/vegas/CMakeLists.txt

@@ -23,3 +23,7 @@ target_compile_definitions(
   vegas PRIVATE ${COMP_DEF}
 )
 
+#--- set compiler options -----------------------------------------------------
+target_compile_options(
+  vegas PRIVATE -fPIC
+)