diff --git a/src/common.mk b/src/common.mk
index 5087288f3..68f1f6490 100644
--- a/src/common.mk
+++ b/src/common.mk
@@ -82,13 +82,39 @@ endif
 QUOTE_NATIVE = $(call QUOTE_ARG,$(call NATIVEPATH,$1))
 ROOT_DIR := $(dir $(realpath $(call NATIVEPATH,$(lastword $(MAKEFILE_LIST)))))
 
-EZCFLAGS := -S -fno-autolink -fno-addrsig -fno-math-errno -ffunction-sections -fdata-sections -ffreestanding
-EZCFLAGS += -Wall -Wextra -Wimplicit-float-conversion -Wimplicit-int-float-conversion -Oz
-EZCFLAGS += -D_EZ80 -D__TICE__=1
-EZCFLAGS += -isystem $(call NATIVEPATH,$(ROOT_DIR)libc/include) -I$(call NATIVEPATH,$(ROOT_DIR)ce/include) -I$(call NATIVEPATH,$(ROOT_DIR)fileioc)
-EZCFLAGS += -mllvm -profile-guided-section-prefix=false -mllvm -z80-gas-style
-EZCXXFLAGS := $(EZCFLAGS) -fno-exceptions -fno-rtti
-EZCXXFLAGS += -isystem $(call NATIVEPATH,$(ROOT_DIR)libcxx/include)
+EZLLVMFLAGS :=
+EZLLVMFLAGS += -fno-autolink
+EZLLVMFLAGS += -fno-addrsig
+EZLLVMFLAGS += -fno-threadsafe-statics
+EZLLVMFLAGS += -mllvm -profile-guided-section-prefix=false
+EZLLVMFLAGS += -mllvm -z80-gas-style
+EZLLVMFLAGS += -ffunction-sections
+EZLLVMFLAGS += -fdata-sections
+EZLLVMFLAGS += -fno-math-errno
+
+EZCOMMONFLAGS := -S
+EZCOMMONFLAGS += -ffreestanding
+EZCOMMONFLAGS += $(EZLLVMFLAGS)
+EZCOMMONFLAGS += -Oz
+EZCOMMONFLAGS += -Wall -Wextra -Wshadow
+EZCOMMONFLAGS += -Wimplicit-float-conversion -Wimplicit-int-float-conversion
+EZCOMMONFLAGS += -Wimplicit-int-conversion
+EZCOMMONFLAGS += -D_EZ80 -D__TICE__=1
+
+EZLIBCINCLUDE := -isystem $(call NATIVEPATH,$(ROOT_DIR)libc/include)
+EZLIBCINCLUDE += -I$(call NATIVEPATH,$(ROOT_DIR)ce/include)
+EZLIBCINCLUDE += -I$(call NATIVEPATH,$(ROOT_DIR)fileioc)
+
+EZLIBCXXINCLUDE := -isystem $(call NATIVEPATH,$(ROOT_DIR)libcxx/include)
+
+EZCFLAGS := $(EZCOMMONFLAGS) $(EZLIBCINCLUDE)
+
+# The C++ standard requires libcxx headers to be searched before libc headers
+# this means include/c++/math.h must be included before include/math.h
+EZCXXFLAGS := $(EZCOMMONFLAGS) $(EZLIBCXXINCLUDE) $(EZLIBCINCLUDE)
+EZCXXFLAGS += -fno-exceptions
+EZCXXFLAGS += -fno-rtti
+
 EZASFLAGS := -march=ez80+full
 EZASFLAGS += --defsym __TICE__=1
 
diff --git a/src/crt/lltof.c b/src/crt/lltof.c
index 4d5c9a84a..b475d6ddf 100644
--- a/src/crt/lltof.c
+++ b/src/crt/lltof.c
@@ -4,7 +4,7 @@
 
 float _lltof_c(long long x)
 {
-    uint8_t exponent = x ? __builtin_clrsbll(x) : LLONG_WIDTH - 1;
+    uint8_t exponent = x ? ((uint8_t)__builtin_clrsbll(x)) : LLONG_WIDTH - 1;
     if (exponent >= LLONG_WIDTH - LONG_WIDTH) {
         return (float)((long)x);
     }
diff --git a/src/crt/ulltof.c b/src/crt/ulltof.c
index 568ad7ddd..058a78c9c 100644
--- a/src/crt/ulltof.c
+++ b/src/crt/ulltof.c
@@ -4,7 +4,7 @@
 
 float _ulltof_c(unsigned long long x)
 {
-    uint8_t exponent = x ? __builtin_clzll(x) : ULLONG_WIDTH;
+    uint8_t exponent = x ? ((uint8_t)__builtin_clzll(x)) : ULLONG_WIDTH;
     if (exponent >= ULLONG_WIDTH - ULONG_WIDTH) {
         return (float)((unsigned long)x);
     }
diff --git a/src/libc/fgetc.c b/src/libc/fgetc.c
index feaa5e9ab..6a0f395c7 100644
--- a/src/libc/fgetc.c
+++ b/src/libc/fgetc.c
@@ -5,9 +5,12 @@ int __attribute__((weak)) fgetc(FILE *stream)
 {
     int c;
 
-    if (stream == NULL ||
-        stream == stdout ||
-        stream == stderr)
+    if (stream == NULL)
+    {
+        return EOF;
+    }
+
+    if (stream == stdout || stream == stderr)
     {
         c = EOF;
     }
diff --git a/src/libc/fgets.c b/src/libc/fgets.c
index 7a9d82f47..bd39b4200 100644
--- a/src/libc/fgets.c
+++ b/src/libc/fgets.c
@@ -18,7 +18,7 @@ char* __attribute__((weak)) fgets(char *__restrict str, int num, FILE *__restric
         {
             break;
         }
-        *p++ = c;
+        *p++ = (char)c;
         if (c == '\n')
         {
             break;
diff --git a/src/libc/float64_rounding.c b/src/libc/float64_rounding.c
index 592dbdcd7..11236835e 100644
--- a/src/libc/float64_rounding.c
+++ b/src/libc/float64_rounding.c
@@ -75,7 +75,7 @@ long long llroundl(long double x) {
     FE_UPWARD     == softfloat_round_max)
 
 // assumes fenv.h macros match softfloat_roundingModes
-#define GET_FENV_SOFTFLOAT_ROUNDING() (fegetround())
+#define GET_FENV_SOFTFLOAT_ROUNDING() ((uint_fast8_t)fegetround())
 
 #else
     static uint_fast8_t GET_FENV_SOFTFLOAT_ROUNDING(void) {
diff --git a/src/libc/fputc.c b/src/libc/fputc.c
index c2b575bcf..78dc905ed 100644
--- a/src/libc/fputc.c
+++ b/src/libc/fputc.c
@@ -5,7 +5,12 @@ int __attribute__((weak)) fputc(int c, FILE *stream)
 {
     int ret;
 
-    if (stream == NULL || stream == stdin)
+    if (stream == NULL)
+    {
+        return EOF;
+    }
+
+    if (stream == stdin)
     {
         ret = EOF;
     }
diff --git a/src/libc/fread.c b/src/libc/fread.c
index af2f63191..4fdac1179 100644
--- a/src/libc/fread.c
+++ b/src/libc/fread.c
@@ -24,7 +24,7 @@ size_t __attribute__((weak)) fread(void *ptr, size_t size, size_t count, FILE *_
             {
                 break;
             }
-            *p++ = c;
+            *p++ = (char)c;
         }
 
         return count;
diff --git a/src/libc/gmtime.c b/src/libc/gmtime.c
index 0a99ddd8d..270328f3f 100644
--- a/src/libc/gmtime.c
+++ b/src/libc/gmtime.c
@@ -82,7 +82,7 @@ struct tm *gmtime(const time_t *tp)
         tm2.tm_min++;
     }
 
-    tm2.tm_sec = t;
+    tm2.tm_sec = (int)t;
 
     return &tm2;
 }
diff --git a/src/libc/printf/nanoprintf.c b/src/libc/printf/nanoprintf.c
index 628236740..3365b1b15 100644
--- a/src/libc/printf/nanoprintf.c
+++ b/src/libc/printf/nanoprintf.c
@@ -18,7 +18,7 @@
 
 static void npf_putc_std(int c, void *ctx) {
   (void)ctx;
-  outchar(c);
+  outchar((char)c);
 }
 
 static void npf_fputc_std(int c, void *ctx) {
diff --git a/src/libc/printf/nanoprintf.h b/src/libc/printf/nanoprintf.h
index 9ecde52f8..99d06fc7c 100644
--- a/src/libc/printf/nanoprintf.h
+++ b/src/libc/printf/nanoprintf.h
@@ -766,9 +766,9 @@ static npf_cnt_putc_ctx_t pc_cnt;
 #endif
 
 static void npf_putc_cnt(int c, void *ctx) {
-  npf_cnt_putc_ctx_t *pc_cnt = (npf_cnt_putc_ctx_t *)ctx;
-  ++pc_cnt->n;
-  pc_cnt->pc(c, pc_cnt->ctx); // sibling-call optimization
+  npf_cnt_putc_ctx_t *pc_putc_cnt = (npf_cnt_putc_ctx_t *)ctx;
+  ++pc_putc_cnt->n;
+  pc_putc_cnt->pc(c, pc_putc_cnt->ctx); // sibling-call optimization
 }
 
 #ifdef NANOPRINTF_STATIC_GLOBALS
diff --git a/src/libc/strftime.c b/src/libc/strftime.c
index 1c08e5637..126a55c8a 100644
--- a/src/libc/strftime.c
+++ b/src/libc/strftime.c
@@ -81,7 +81,7 @@ size_t strftime(char *__restrict s, size_t n, const char *__restrict f, const st
 
     while (s + 1 < e && *f)
     {
-        int c = *f++;
+        char c = *f++;
         int val;
 
         if (c != '%')
diff --git a/src/makefile.mk b/src/makefile.mk
index 2b453fc38..777e7499d 100644
--- a/src/makefile.mk
+++ b/src/makefile.mk
@@ -314,10 +314,39 @@ MATH_ERRNO = -fno-math-errno
 endif
 
 # define the compiler/assembler flags
-EZLLVMFLAGS = -mllvm -profile-guided-section-prefix=false -mllvm -z80-gas-style -ffunction-sections -fdata-sections -fno-addrsig -fno-autolink -fno-threadsafe-statics $(MATH_ERRNO)
-EZCOMMONFLAGS = -nostdinc -isystem $(call QUOTE_ARG,$(call FORWARD_PATH,$(CEDEV_TOOLCHAIN)/include)) -I$(SRCDIR) -Xclang -fforce-mangle-main-argc-argv $(EZLLVMFLAGS) -D__TICE__=1 $(CC_CUSTOMFILE)
-EZCFLAGS = $(EZCOMMONFLAGS) $(CFLAGS) $(CC_DEBUG)
-EZCXXFLAGS = $(EZCOMMONFLAGS) -isystem $(call QUOTE_ARG,$(call FORWARD_PATH,$(CEDEV_TOOLCHAIN)/include/c++)) -fno-exceptions -fno-use-cxa-atexit $(CXXFLAGS) $(CC_DEBUG)
+
+EZLLVMFLAGS =
+EZLLVMFLAGS += -fno-autolink
+EZLLVMFLAGS += -fno-addrsig
+EZLLVMFLAGS += -fno-threadsafe-statics
+EZLLVMFLAGS += -mllvm -profile-guided-section-prefix=false
+EZLLVMFLAGS += -mllvm -z80-gas-style
+EZLLVMFLAGS += -ffunction-sections
+EZLLVMFLAGS += -fdata-sections
+EZLLVMFLAGS += $(MATH_ERRNO)
+
+EZCOMMONFLAGS =
+EZCOMMONFLAGS += -nostdinc
+EZCOMMONFLAGS += -Xclang -fforce-mangle-main-argc-argv
+EZCOMMONFLAGS += $(EZLLVMFLAGS)
+EZCOMMONFLAGS += -D__TICE__=1
+EZCOMMONFLAGS += $(CC_CUSTOMFILE)
+
+EZLIBCINCLUDE = -isystem $(call QUOTE_ARG,$(call FORWARD_PATH,$(CEDEV_TOOLCHAIN)/include))
+EZLIBCINCLUDE += -I$(SRCDIR)
+
+EZLIBCXXINCLUDE = -isystem $(call QUOTE_ARG,$(call FORWARD_PATH,$(CEDEV_TOOLCHAIN)/include/c++))
+
+EZCFLAGS = $(EZCOMMONFLAGS) $(EZLIBCINCLUDE)
+EZCFLAGS += $(CFLAGS) $(CC_DEBUG)
+
+# The C++ standard requires libcxx headers to be searched before libc headers
+# this means include/c++/math.h must be included before include/math.h
+EZCXXFLAGS = $(EZCOMMONFLAGS) $(EZLIBCXXINCLUDE) $(EZLIBCINCLUDE)
+EZCXXFLAGS += -fno-exceptions
+EZCXXFLAGS += -fno-use-cxa-atexit
+EZCXXFLAGS += $(CXXFLAGS) $(CC_DEBUG)
+
 EZLTOFLAGS = $(EZLLVMFLAGS) $(LTOFLAGS)
 EZASFLAGS = -march=ez80+full $(ASFLAGS)