gfxstream: USE_MAGMA --> GFXSTREAM_ENABLE_HOST_MAGMA

Name change to be consistent with subsequent commit.

BUG=311486792
TEST=compile

Change-Id: If0f62c9d81ad16128f2b1a3c9b032e841d6fa28b
diff --git a/host/RenderThread.cpp b/host/RenderThread.cpp
index 74cee30..abe4fcc 100644
--- a/host/RenderThread.cpp
+++ b/host/RenderThread.cpp
@@ -303,7 +303,7 @@
         tInfo.m_vkInfo.emplace();
     }
 
-#if USE_MAGMA
+#if GFXSTREAM_ENABLE_HOST_MAGMA
     tInfo.m_magmaInfo.emplace(mContextId);
 #endif
 
@@ -566,7 +566,7 @@
             // try to process some of the command buffer using the Magma
             // decoder
             //
-#if USE_MAGMA
+#if GFXSTREAM_ENABLE_HOST_MAGMA
             if (tInfo.m_magmaInfo && tInfo.m_magmaInfo->mMagmaDec)
             {
                 last = tInfo.m_magmaInfo->mMagmaDec->decode(readBuf.buf(), readBuf.validData(),
diff --git a/host/RenderThreadInfo.h b/host/RenderThreadInfo.h
index 341b0a2..636421e 100644
--- a/host/RenderThreadInfo.h
+++ b/host/RenderThreadInfo.h
@@ -25,7 +25,7 @@
 #include "RenderThreadInfoGl.h"
 #include "RenderThreadInfoVk.h"
 
-#if USE_MAGMA
+#if GFXSTREAM_ENABLE_HOST_MAGMA
 #include "RenderThreadInfoMagma.h"
 #endif
 
@@ -58,7 +58,7 @@
     std::optional<gl::RenderThreadInfoGl> m_glInfo;
     std::optional<vk::RenderThreadInfoVk> m_vkInfo;
 
-#if USE_MAGMA
+#if GFXSTREAM_ENABLE_HOST_MAGMA
     std::optional<RenderThreadInfoMagma> m_magmaInfo;
 #endif
 
diff --git a/host/meson.build b/host/meson.build
index 0274546..1d9b4c8 100644
--- a/host/meson.build
+++ b/host/meson.build
@@ -95,10 +95,10 @@
 endif
 
 if use_magma
-  gfxstream_host_args += '-DUSE_MAGMA=1'
+  gfxstream_host_args += '-DGFXSTREAM_ENABLE_HOST_GLES=1'
   drm_dep = dependency('libdrm')
 else
-  gfxstream_host_args += '-DUSE_MAGMA=0'
+  gfxstream_host_args += '-DGFXSTREAM_ENABLE_HOST_GLES=0'
 endif
 
 #===============#