[R] reformat build scripts (#9540)

R-package/src/Makevars.in

@@ -5,9 +5,12 @@ ENABLE_STD_THREAD=1
 
 CXX_STD = CXX17
 
-XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
-           -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\
-           -DDMLC_LOG_CUSTOMIZE=1
+XGB_RFLAGS = \
+    -DXGBOOST_STRICT_R_MODE=1 \
+    -DDMLC_LOG_BEFORE_THROW=0 \
+    -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) \
+    -DDMLC_DISABLE_STDIN=1 \
+    -DDMLC_LOG_CUSTOMIZE=1
 
 # disable the use of thread_local for 32 bit windows:
 ifeq ($(R_OSTYPE)$(WIN),windows)
@@ -15,9 +18,25 @@ ifeq ($(R_OSTYPE)$(WIN),windows)
 endif
 $(foreach v, $(XGB_RFLAGS), $(warning $(v)))
 
-PKG_CPPFLAGS=  -I$(PKGROOT)/include -I$(PKGROOT)/dmlc-core/include -I$(PKGROOT)/rabit/include -I$(PKGROOT) $(XGB_RFLAGS)
-PKG_CXXFLAGS= @OPENMP_CXXFLAGS@ @ENDIAN_FLAG@ -pthread $(CXX_VISIBILITY)
-PKG_LIBS = @OPENMP_CXXFLAGS@ @OPENMP_LIB@ @ENDIAN_FLAG@ @BACKTRACE_LIB@ -pthread
+PKG_CPPFLAGS = \
+    -I$(PKGROOT)/include \
+    -I$(PKGROOT)/dmlc-core/include \
+    -I$(PKGROOT)/rabit/include \
+    -I$(PKGROOT) \
+    $(XGB_RFLAGS)
+
+PKG_CXXFLAGS = \
+    @OPENMP_CXXFLAGS@ \
+    @ENDIAN_FLAG@ \
+    -pthread \
+    $(CXX_VISIBILITY)
+
+PKG_LIBS = \
+    @OPENMP_CXXFLAGS@ \
+    @OPENMP_LIB@ \
+    @ENDIAN_FLAG@ \
+    @BACKTRACE_LIB@ \
+    -pthread
 
 OBJECTS= \
     ./xgboost_R.o \

R-package/src/Makevars.win

@@ -5,9 +5,12 @@ ENABLE_STD_THREAD=0
 
 CXX_STD = CXX17
 
-XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
-           -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\
-           -DDMLC_LOG_CUSTOMIZE=1
+XGB_RFLAGS = \
+    -DXGBOOST_STRICT_R_MODE=1 \
+    -DDMLC_LOG_BEFORE_THROW=0 \
+    -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) \
+    -DDMLC_DISABLE_STDIN=1 \
+    -DDMLC_LOG_CUSTOMIZE=1
 
 # disable the use of thread_local for 32 bit windows:
 ifeq ($(R_OSTYPE)$(WIN),windows)
@@ -15,9 +18,25 @@ ifeq ($(R_OSTYPE)$(WIN),windows)
 endif
 $(foreach v, $(XGB_RFLAGS), $(warning $(v)))
 
-PKG_CPPFLAGS=  -I$(PKGROOT)/include -I$(PKGROOT)/dmlc-core/include -I$(PKGROOT)/rabit/include -I$(PKGROOT) $(XGB_RFLAGS)
-PKG_CXXFLAGS= $(SHLIB_OPENMP_CXXFLAGS) -DDMLC_CMAKE_LITTLE_ENDIAN=1 $(SHLIB_PTHREAD_FLAGS) $(CXX_VISIBILITY)
-PKG_LIBS = $(SHLIB_OPENMP_CXXFLAGS)  -DDMLC_CMAKE_LITTLE_ENDIAN=1  $(SHLIB_PTHREAD_FLAGS) -lwsock32 -lws2_32
+PKG_CPPFLAGS = \
+    -I$(PKGROOT)/include \
+    -I$(PKGROOT)/dmlc-core/include \
+    -I$(PKGROOT)/rabit/include \
+    -I$(PKGROOT) \
+    $(XGB_RFLAGS)
+
+PKG_CXXFLAGS = \
+    $(SHLIB_OPENMP_CXXFLAGS) \
+    -DDMLC_CMAKE_LITTLE_ENDIAN=1 \
+    $(SHLIB_PTHREAD_FLAGS) \
+    $(CXX_VISIBILITY)
+
+PKG_LIBS = \
+    $(SHLIB_OPENMP_CXXFLAGS) \
+    -DDMLC_CMAKE_LITTLE_ENDIAN=1 \
+    $(SHLIB_PTHREAD_FLAGS) \
+    -lwsock32 \
+    -lws2_32
 
 OBJECTS= \
     ./xgboost_R.o \