aom_configure.cmake: detect PIE and set CONFIG_PIC

Fixes the creation of DT_TEXTREL entries in binaries built with PIE
enabled:
  /usr/bin/ld: warning: creating DT_TEXTREL in a PIE

Bug: b/229626362
Change-Id: I37a0eaf6b7471953d2c8b3f7f903c84cb2acbd2d
(cherry picked from commit 7235e6574663af3d93786f72261a0b2be91e453d)

build/cmake/aom_configure.cmake

diff --git a/build/cmake/aom_configure.cmake b/build/cmake/aom_configure.cmake
index 27b94a9..1a8bae5 100644
--- a/build/cmake/aom_configure.cmake
+++ b/build/cmake/aom_configure.cmake
@@ -110,6 +110,21 @@
 if(BUILD_SHARED_LIBS)
   set(CONFIG_PIC 1)
   set(CONFIG_SHARED 1)
+elseif(NOT CONFIG_PIC)
+  aom_check_c_compiles("pie_check" "
+                        #if !(__pie__ || __PIE__)
+                        #error Neither __pie__ or __PIE__ are set
+                        #endif
+                        extern void unused(void);
+                        void unused(void) {}" HAVE_PIE)
+
+  if(HAVE_PIE)
+    # If -fpie or -fPIE are used ensure the assembly code has PIC enabled to
+    # avoid DT_TEXTRELs: /usr/bin/ld: warning: creating DT_TEXTREL in a PIE
+    set(CONFIG_PIC 1)
+    message(
+      "CONFIG_PIC enabled for position independent executable (PIE) build")
+  endif()
 endif()
 
 if(NOT MSVC)